Papers
137. Alexei Kazarine and Eric D Salin, Volumetric Measurements by Image Segmentation on Centrifugal Microfluidic Platforms in Motion, Lab on a Chip, 2014, DOI: 10.1039/C4LC00609G [abstract]
An image segmentation based method was developed to perform volumetric measurements of liquid aliquots in centrifugal microfluidic platforms in motion. The method was designed to be as automated as possible to allow its applicability to the large variety of available design features that tend to be included on such platforms. Experiments have indicated a relative standard deviation (RSD) of 0.3% for replicate measurements and 1% for same volume aliquots injected into different sized chambers. The versatility of the method in regards to chamber shape and size, liquid colour and platform rotational frequency was demonstrated. This flexibility should allow it to be used for a variety of applications including real time metering of volumes in platforms, quantitative monitoring of a design’s performance in real time and could result in the elimination of metering chambers for some applications.
136. Erin J. Templeton and Eric D. Salin, A novel filtration method integrated on centrifugal microfluidic devices, Microfluidics and Nanofluidics, 2014, Volume 17, Issue 1, pp 245-251
[abstract]
A method has been developed that integrates filters directly into centrifugal microfluidic devices. This technique is suitable for both rapid prototyping and commercial applications. Commercially available filter paper was sealed into the centrifugal microfluidic device with a simple manual fabrication procedure. The method was validated using soil slurry in water and a variety of filter papers with pore sizes ranging from 0.7 to 11 μm. Filtration times of 4 s to several minutes were obtained for 100 μL samples depending on the type of filter paper and rotation rate utilized. The validity of the method was demonstrated by assessing the amount of light lost due to the scatter or absorption caused by particles in the filtered sample while the device was in motion. Filtration and sedimentation were compared and after 30 min of centrifugation, sedimentation had not removed particles as well as filtration. This technique opens up centrifugal microfluidic devices to a wide range of samples.
135. Matthew C. R. Kong and Eric D. Salin, Spectrophotometric Determination of Aqueous Sulfide on a Pneumatically Enhanced Centrifugal Microfluidic Platform, Analytical Chemistry, 2012, 84 (22), pp 10038-10043
[abstract]
A pneumatically enhanced centrifugal microfluidic platform was developed for rapid spectrophotometric determination of aqueous sulfide. This platform performs an automated analysis based on the reaction between hydrogen sulfide and N,N-dimethyl-p-phenylenediamine in the presence of iron(III) chloride to form Methylene Blue. The platform design minimizes the number of integrated valves required, compared to other centrifugal systems, significantly improving the ease of fabrication. The sequential analytical procedure and spectrophotometric analyses were performed directly on-disk, demonstrating significant advantages in portability and cost over conventional analytical methods. This method allows for rapid and precise determination of aqueous sulfide in the concentration range of 0.4–2.0 mg L–1, which can be extended by a pneumatically induced, on-disk serial dilution to 6.0 mg L–1. A detection limit of 0.4 mg L–1 was calculated for this pneumatically enhanced method.
134. Alexei Kazarine, Matthew C. R. Kong, Erin J. Templeton and Eric D. Salin, Automated Liquid-Liquid Extraction by Pneumatic Recirculation on a Centrifugal Microfluidic Platform, Analytical Chemistry, 2012, 84 (16), pp 6939-6943
[abstract]
In this technical note, a liquid-liquid extraction technique was performed using pneumatic liquid recirculation on a centrifugal microfluidic device. Non-contact pneumatic pumping enabled a multi-cycle liquid-liquid extraction process using aqueous iodine in a potassium iodide solution and hexadecane while requiring a minimal amount of space on the device. The extraction process was completely automated on the device following sample introduction and required only 50 s for each extraction cycle. The pumping rate achieved during liquid recirculation was 120 ± 10 μL/min. A recycling process such as the one demonstrated would be difficult to implement in a conventional centrifugal microfluidic system.
133. Matthew C.R. Kong and Eric D. Salin, Micromixing by pneumatic agitation on continually rotating centrifugal microfluidic platforms, Microfluidics and Nanofluidics, 2012, Volume 13, Issue 3, pp 519-525
[abstract]
A highly effective pneumatic technique for mixing liquids on centrifugal microfluidic platforms is demonstrated and characterized. While a centrifugal platform is rotating, a stream of compressed gas is used to agitate liquids on the platform. This technique is implemented in a non-contact fashion and allows mixing without the need to alter the rotational frequency or direction of the centrifugal platform. Pneumatic agitation causes rapid mixing of the liquids and achieves homogeneity in 11.2 ± 1.2 s while rotating at 450 rpm (7.5 Hz), a 30-fold improvement compared to conventional mixing by interfacial diffusion. The mixing operation is shown to be equally effective when implemented over a range of rotational frequencies from 450 rpm (7.5 Hz) to 1,500 rpm (25 Hz).
132. Matthew C.R. Kong, Adam P. Bouchard and Eric D. Salin, Displacement Pumping of Liquids Radially Inward on Centrifugal Microfluidic Platforms in Motion, Micromachines, 2012, 3, 1-9.
[abstract]
We describe two novel centrifugal microfluidic platform designs that enable passive pumping of liquids radially inward while the platform is in motion. The first design uses an immiscible liquid to displace an aqueous solution back towards the center of the platform, while the second design uses an arbitrary pumping liquid with a volume of air between it and the solution being pumped. Both designs demonstrated the ability to effectively pump 55% to 60% of the solution radially inward at rotational frequencies as low as 400 rpm (6.7 Hz) to 700 rpm (11.7 Hz). The pumping operations reached completion within 120 s and 400 s respectively. These platform designs for passive pumping of liquids do not require moving parts or complex fabrication techniques. They offer great potential for increasing the number of sequential operations that can be performed on centrifugal microfluidic platforms, thereby reducing a fundamental limitation often associated with these platforms.
131. Matthew C.R. Kong and Eric D. Salin, A Valveless Pneumatic Fluid Transfer Technique Applied To Standard Additions on a Centrifugal Microfluidic Platform, Analytical Chemistry, 2011, 83 (23), pp 9186-9190
[abstract]
This paper demonstrates a valveless pneumatic fluid transfer technique applicable to centrifugal microfluidic platforms. The technique involves using compressed gas to generate a pneumatic force, which works together with the centrifugal force to control and direct fluid flow. Fluid can be pneumatically transferred from chamber to chamber, greatly decreasing the number of conventional valves required in a multistep process. By varying the rotational frequency of the centrifugal microfluidic platform while pneumatic force is applied, sequential fluid transfer steps can be achieved. The effectiveness of this fluid transfer method is demonstrated by performing a standard additions calibration. This technique is shown to be robust, easy to implement, and greatly reduces the design limitations traditionally associated with centrifugal microfluidic platforms.
130. Matthew C.R. Kong and Eric D. Salin, Pneumatic Flow Switching on Centrifugal Microfluidic Platforms In Motion, Analytical Chemistry, 2011, 83 (3), pp 1148-1151
[abstract]
This paper describes a flow switching technique applicable to centrifugal microfluidic platforms, using a regulated stream of compressed gas. This pneumatic flow switching technique allows for flow control at a T-shaped junction between one inlet channel and two outlet channels. This technique provides a noncontact, robust, and efficient method for switching the direction of fluid flow while a disk is rotating at relatively low frequencies. The switching operation can be implemented reproducibly with applied gas flow rates between 17 and 58 L min−1 and rotational frequencies between 400 rpm (6.6 Hz) and 1200 rpm (20 Hz).
129. Grazyna Wilczek-Vera and Eric D. Salin, Understanding Fluorescence Measurements through a Guided-Inquiry and Discovery Experiment in Advanced Analytical Laboratory, J. Chem. Educ., 2011, 88 (2), pp 216-219.
[abstract]
An experiment on fluorescence spectroscopy suitable for an advanced analytical laboratory is presented. Its conceptual development used a combination of the expository and discovery styles. The “learn-as-you-go” and direct “hands-on” methodology applied ensures an active role for a student in the process of visualization and discovery of concepts. In this multistep experiment, students start their exploration from the observation of a dark current and the scattered ambient light. Subsequently, they explore properties of the visible light. Signal processing techniques are introduced. After finding the excitation and emission wavelengths for fluorescein, students are able to determine the gross calibration curve. The inner filter effect and spectral shift phenomenon are clearly demonstrated. Using the linear dynamic range of the calibration curve, students then determine the concentration of an unknown. The pH effect on the emission intensity of fluorescence is also studied.
128. Adam P. Bouchard, David A. Duford and Eric D. Salin, Non-contact addition, metering and distribution of liquids into centrifugal microfluidic devices in motion, Analytical Chemistry, 2010, 82 (20), pp 8386-8389.
[abstract]
A three-dimensional structure was constructed to demonstrate contact-free liquid addition and distribution to a conventional centrifugal microfluidic platform. The structure allowed a continuous stream of liquid to be added to the rotating platform where it was dispensed and metered to a series of reservoirs with 9% relative standard deviation of the volume. An off-platform generated gradient was used to demonstrate this design's potential to make gradient centrifugal microfluidic chromatography possible without the use of platform space for liquid storage. The system demonstrates a convenient and versatile "World-to-Chip" or more appropriately, World-to-Disk, macro-to-micro interface.
127. Matthew C.R. Kong and Eric D. Salin, Pneumatically pumping fluids radially inward on centrifugal microfluidic platforms in motion, Analytical Chemistry, 2010, 82 (19), pp 8039-8041.
[abstract]
This paper describes a pumping technique applicable to centrifugal microfluidic platforms, involving the use of a regulated stream of compressed gas to pump liquid radially inward and toward the center of the platform while spinning. This technique provides a non-contact method for pumping fluids and is highly efficient, requiring only approximately 60 s to reach completion. This pumping operation can be attained with an applied gas flow rate of 58.8 L min-1, while the platform is rotated at frequencies less than 180 rpm (3.0 Hz).
126. Yongqing Xi, Erin J. Templeton, Eric D. Salin, Rapid simultaneous determination of nitrate and nitrite on a centrifugal microfluidic device, Talanta, 2010, 82, 1612-1615.
[abstract]
A centrifugal microfluidic device was developed for the rapid sequential determination of two critical environmental species, nitrate and nitrite, in water samples. The nitrate is reduced to nitrite and the nitrite is derivatized. The analytes are determined spectrophotometrically through the disc with a 1.4 mm pathlength. The detection limits are 0.05 and 0.16 mg L-1 for nitrite and nitrate respectively. The use of powdered reagents, the 100 µL sample required and the design of the device suggest that it would be suitable for field use.
125. Yongqing Xi, David A. Duford, Eric D. Salin, Automated liquid-solid extraction of pyrene from soil on centrifugal microfluidic devices, Talanta, 2010, 82, 1072-1076.
[abstract]
Organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) are present in the environment in increasing concentrations and so are of growing concern. Monitoring these species, particularly on-site, can be both difficult and expensive. This paper presents a novel miniaturised magnetically actuated liquid-solid extraction unit integrated in tandem with a filtration unit and a detection unit on a single centrifugal microfluidic device. A demonstration analyte, pyrene, was rapidly extracted and quantified by UV-absorbance from multiple soil samples. The system showed excellent performance for a system designed for field use. Characterization of two types of passive valves was performed along with an extraction time efficiency study. The system provides a factor of 150 reduction in sample weights and extraction solvent volumes and provides statistically similar recoveries to the conventional method with a pyrene detection limit of 1 ppm (0.03 µg absolute detection limit). The reduction in time and solvent and the potential for field use suggest that this device type may be valuable for environmental monitoring.
124. Josiane P. Lafleur, Andrien A. Rackov, Scott McAuley, Eric D. Salin, Miniaturised centrifugal solid phase extraction platforms for in-field sampling, pre-concentration and spectrometric detection of organic pollutants in aqueous samples, Talanta, 2010, 81(1-2), 722-726.
[abstract]
Great variations in pollutant concentrations are observed in the environment and pre-concentration is often required to detect trace contaminants in water samples. This paper presents a novel solid phase-extraction device integrated onto a centrifugal microfluidic platform for rapid on-site pre-concentration and screening of organic contaminants in aqueous samples. In-column fluorescence and absorbance measurements are obtained directly from an analyte trapped on the top of a solid phase extraction microcolumn. Results are presented for the representative fluorophore fluorescein and the polycyclic aromatic hydrocarbon anthracene. An absolute detection limit of 20 ng was obtained for anthracene using a simple light emitting diode for fluorescence excitation. One of the main advantages of this device is that only a simple motor is needed to induce liquid flow, making simultaneous on-site extraction and measurement of multiple samples easy while minimizing sample losses and contamination.
123. Josiane P. Lafleur and Eric D. Salin, Pre-concentration of trace metals on centrifugal microfluidic discs with direct determination by Laser Ablation Inductively Coupled Plasma Mass Spectrometry, Journal of Analytical Atomic Spectrometry, 2009, 24(11), 1511-1516.
[abstract]
Solid Phase Extraction (SPE) is commonly used for pre-concentration and matrix removal in trace metal determinations. We present a novel centrifugal microfluidic device for field sampling and on-site pre-concentration of water samples. Metal-8-hydroxyquinoline complexes are adsorbed onto miniature C18-bonded silica gel columns on centrifugal microfluidic discs. Laser Ablation (LA) is used to directly vaporize the analytes from the column, instead of eluting the pre-concentrated analytes for introduction in an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) by conventional solution nebulization. Absolute detection limits ranging between 0.1 and 12 ng were obtained for Ni, Cu, V, Pb and Co in drinking water Certified Reference Materials (CRMs). These centrifugal devices require only 1 - 600 µL samples and necessitate no more than a simple motor to actuate fluid flow. The discs can be used to perform multiple extractions simultaneously as well as allowing the easy storage of samples before transport to the laboratory for LA-ICP-MS analysis.
122. Angela LaCroix-Fralish,Jennifer Clare, Eric D. Salin and Cameron D. Skinner, A Centrifugal Microanalysis System for the Determination of Nitrite and Hexavalent Chromium, Talanta, 2009, 80(2), 670-675.
[abstract]
A centrifugal microanalysis system using spectrophotometric detection has been developed for the determination of nitrite and chromium VI. The system was designed to illustrate the potential of centrifugal microfluidic systems for on-site (field) analysis of waters. The performance was significantly better than manual/visual field test systems and approaches that of bench top systems with detection limits of 0.008 mg·L-1 NO2--N and 0.03 mg·L-1 Cr6+. The system used pre-loaded solid reagents on the disc, providing ease of use, and could process up to 24 samples simultaneously. Precision was enhanced by the use of a multi wavelength ratiometric blank estimation technique.
121. Angela LaCroix-Fralish, Erin J. Templeton, Eric D. Salin and Cameron D. Skinner, A rapid prototyping technique for valves and filters in centrifugal microfluidic devices, Lab on a Chip, 2009, 9(21), 3151-3154.
[abstract]
Using short lengths of fused silica capillary tubing embedded in the disk, a system for valving and filtering samples on centrifugal microfluidic devices has been designed and implemented. Sedimentation of turbid samples and transfer of the clear supernatant was also accomplished. Also demonstrated is the transfer of the liquid through a second capillary valve to the final reservoir. By controlling rotational speed, sedimentation and multiple step valving operations are readily implemented and easily prototyped.
120. Kevin Bemben, Hing Man Chan and Eric D. Salin, Laser implemented depth profiling and surfacing cleaning of human hair using laser ablation inductively coupled plasma mass, Journal of Analytical Atomic Spectrometry, 2009, 24(4), 515-517
[abstract]
Laser ablation ICP-MS appears to be capable of employing the laser to both depth profile human hair and to remove exogenous material, thereby minimizing sample preparation requirements. © The Royal Society of Chemistry 2009.
119. David A. Duford, Dan D. Peng and Eric D. Salin, Magnetically driven solid sample preparation for centrifugal microfluidic devices, Analytical Chemistry, 2009, 81(11), 4581-4584
[abstract]
A prototype for solid sample preparation on centrifugal microfluidic devices has been designed and characterized. The system uses NdFeB magnets in both the centrifugal device and a fixed base. As the centrifugal device rotates, the magnets move and spin in their chambers creating a pulverizing mechanical motion. This technique was successfully applied to the dissolution of potassium ferricyanide (K3[Fe(CN)6]), a hard colored crystal. A 0.10 g sample was completely dissolved in 3 s in 1.0 mL of water while rotating at 1000 rpm. This is a 300-fold improvement over static dissolution. © 2009 American Chemical Society.
118. Josiane P. Lafleur and Eric D. Salin, Speciation of chromium by high performance thin layer chromatography with direct determination by laser ablation inductively coupled plasma mass spectrometry, Analytical Chemistry, 2008, 80(17), 6821-6823
[abstract]
It is of considerable importance to be able to distinguish metallic species because their toxicity depends on their chemical form. Therefore, the analysis of environmental samples can be enhanced by the combination of high-performance thin-layer chromatography (HPTLC) with laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). In this study, Cr3+ and Cr6+ were separated on silica gel HPTLC plates using aqueous mobile phases. Separation was achieved in seconds with retardation factors (Rf) of 0 and 1 for Cr3+ and Cr6+, respectively. LA was used to volatilize the chromium species directly from the chromatographic material prior to ICPMS detection. A linear calibration was obtained, and detection limits (3s) of 6 ng for Cr6+ and 0.4 ng for Cr3+ were achieved with precision ranging from 3 to 40% at the 95% confidence level. The silicon present in the stationary phase was used as an internal standard. This procedure allows for a rapid separation and quantification, requires only 0.5 µL of sample, and lower detection limits can be achieved through preconcentration.
117. Lam, Rebecca; Salin, Eric D. Direct analysis of analyte–laden chromatographic stationary phase by induction–heating electrothermal vaporizer with inductively coupled plasma atomic emission spectroscopy. Canadian Journal of Chemistry (2008), 86(6), 586-589
[abstract]
We describe the inductively heated electrothermal vaporization of 8-hydroxyquinolate complexes of Cd, Pb, and Zn adsorbed onto C18-bonded silica gel with inductively coupled plasma atomic emission spectroscopic detection. The metal complexes were adsorbed onto the chromatographic stationary phase using a solid-phase extraction procedure. Instead of eluting the complexes from the stationary phase, the solid phase was directly vaporized into the plasma. Absolute detection limits for this method ranged from 0.3 to 3 µg.
116. Josiane P. Lafleur and Eric D. Salin, A miniature centrifugal chromatographic device for the pre-concentration and determination of lead in aqueous samples. Proceedings of MicroTAS 2007, Eleventh International Conference on Miniaturized Systems for Chemistry and Life Sciences, ISBN: 978-0-9798064-0-7, (2007), Vol 2, 1441-1443. (Full conference paper published in proceedings)
[abstract]
Solid Phase Extraction (SPE) columns were implemented on centrifugal microfluidic
devices where the analyte was sampled directly by Laser Ablation (LA) Inductively
Coupled Plasma-Mass Spectrometry (ICP-MS). The direct analysis of lead-8-
hydroxyquinoline complexes adsorbed onto C18-bonded silica gel is demonstrated.
115. Lam, Rebecca; Salin, Eric D., Direct multielement determination of human hair by induction-heating electrothermal vaporization with ICP-MS. Journal of Analytical Atomic Spectrometry (2007), 22(11), 1430-1433
[abstract]
Conventional methods of hair anal. using instruments, such as inductively coupled plasma-mass spectrometry (ICP-MS), typically require a digestion step that has many disadvantages. As an alternative, we report on the application of an induction heating-electrothermal vaporizer (IH-ETV) with ICP-MS detection for direct multielement detn. of sub-milligram amts. of solid hair material. As, Cd, Cu, Hg, Pb and Zn were detd. using powd. hair std. ref. materials (SRMs) with IH-ETV-ICP-MS. Transient profiles reveal that powd. hair SRMs and hair strands have the same analyte signal shapes, while solns. have different shapes. External stds. calibration using SRMs gives results that agree with the certified values, with the precision of detn. ranging from 9-54%. Abs. detection limits ranged from 0.01-8 ng. These values are sufficiently low that they should allow the detn. of metals at natural levels in a single human hair strand.
114. Legrand, Melissa; Lam, Rebecca; Passos, Carlos Jose Sousa; Mergler, Donna; Salin, Eric D.; Chan, Hing Man. Analysis of Mercury in Sequential Micrometer Segments of Single Hair Strands of Fish-Eaters. Environmental Science & Technology (2007), 41(2), 593-598
[abstract]
Although it has been established that mercury (Hg) can be detected in single hair strands using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), calibration remains a challenge due to the lack of well-characterized matrix-matched standards. We concurrently evaluated two strategies for quantifying Hg signals in single hair strands using LA-ICP-MS. The main objective was to obtain time-resolved Hg concentrations in single hair strands of fish-eaters that would correspond to the changes of their body burden over time. Experiments were conducted using hair samples collected from 10 individuals. The first experiment involved the construction of a calibration curve with four powdered hair standard reference materials (SRMs) with a range of Hg concentrations (0.573-23.2 mg/kg). An internal standard, sulfur, as 34S, was applied to correct for ablation efficiency for both the hair strands and the SRMs. Results showed a linear relationship (R 2 = 0.899) between the ratio of 202Hg to 34S obtained by LA-ICP-MS and the certified total Hg concentration in the SRMs. Using this calibration curve, average Hg concentrations of 10 shots within a 1-cm segment of a hair strand were calculated and then compared to the total Hg concentrations in the matched 1-cm segment as measured by cold vapor atomic absorption spectrometry (CV-AAS). A significant difference (p < 0.05) was observed. The difference could be attributed to the highly variable ablation/sampling process caused by the use of the laser on the hair powder SRM pellets and the difference in the physical properties of the SRMs. An alternative approach was adopted to quantify consecutive 202Hg to 34S ratios by calibrating the signals against the average Hg concentration of the matched hair segment as measured by CV-AAS. Consecutive daily Hg deposition in single hairs of fish eaters was determined. Results showed that apparent daily changes in Hg concentrations within a hair segment that corresponds to 1 month of hair growth. In addition, a significant decreasing or increasing time-trend was observed. The difference between the minimum and maximum Hg concentration within each individual corresponded to a change of 26-40%. Our results showed that LA-ICP-MS can be used to reconstruct time-resolved Hg exposure in micrometer segments of a single hair strand.
113. Duford, David A.; Lafleur, Josiane P.; Lam, Rebecca; Skinner, Cameron D.; Salin, Eric D., Induction heating-electrothermal vaporization for direct mercury determination in a single human hair by atomic fluorescence and atomic absorption spectrometry. J. Anal. At. Spectrom., 2007, 22, 326 - 329
[abstract]
A compact, rapid and cost-efficient system for the determination of total mercury (Hg) in a single human hair strand is presented. The system uses induction heating-electrothermal vaporization and gold amalgamation trapping in tandem with either atomic fluorescence spectrometry or atomic absorption spectrometry with background correction detection. Using these techniques, detection limits of 0.1 ng or 0.2 µg/g and 0.08 ng or 0.1 µg/g (based on a 0.6 mg sample) of Hg were achieved respectively.
112. Antler, Margaret; Maxwell, E. Jane; Duford, David A.; Salin, Eric D. Online Standard Additions Calibration of Transient Signals for Inductively Coupled Plasma Mass Spectrometry. Analytical Chemistry (2007), 79 (2), pp. 688-694
[abstract]
An online standard additions calibration method for transient signals in ICP-MS is demonstrated in which a small volume of standard is injected as a spike into the sample/carrier stream, overlaying the analyte peak. This technique provides the advantages of conventional standard additions but requires only a single sample run. The method corrects for matrix effects and is suitable for transient signals in which the severity of the matrix effect changes over the analyte peak. The method uses a peak-fitting program to determine the areas of the underlying peak and is shown to be effective for the determination of trace metal concentrations in both a high ionic strength matrix and in a biological matrix (urine). Eight analytes with concentrations in the range of 0.82 mg L-1 to 233.2 mg L-1 in urine were simultaneously determined using a standard spiking solution of 75 mg L-1 injected through a 100 µL loop. The measured concentrations for analytes free of spectral interferences agreed with the certified values, and the precision achieved was comparable to that achieved by the certifying agency. Using a conventional cross flow nebulizer and Scott-type spray chamber, the accuracy obtained for online standard additions calibration was within 2%, and the precision was within 5%.
111. Lafleur, Josiane P.; Lam, Rebecca; Chan, Hing Man; Salin, Eric D.. Induction heating-electrothermal vaporization for direct mercury analysis of a single human hair strand by inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry (2005), 20(12), 1315-1317.
[abstract]
The direct mercury analysis of a single human hair strand using an induction heating-electrothermal vaporizer (IH-ETV) by inductively coupled plasma mass spectrometry (ICP-MS), was investigated. It was observed that IH-ETV-ICP-MS could easily determine mercury concentrations in a single hair strand using external standards calibration with powdered hair certified reference material (CRM). The detection limit achieved by this method was 20 pg of Hg for a 12 cm strand of hair which meant that only 0.4 cm of hair is needed to detect a natural mercury level of 1 µg g-1. The results show that just one hair strand is sufficient to estimate mercury levels in an individual which is much less than 100 strands required for traditional methods.
110. Antler, Margaret; Salin, Eric; Wilczek-Vera, Grazyna. Teaching data acquisition: An undergraduate experiment in advanced analytical chemistry. Journal of Chemical Education (2005), 82(3), 425-427.
[abstract]
The software-design part of an exercise covering a series of three laboratory experiments that teach chemistry students the basic principles of data acquisition, has been updated by replacing the TurboPascal programming language with Matlab. Prior to starting the experiments, students have a one-hour lecture exposure to Matlab and one lecture on operational amplifiers. In the first experiment students learn about operational amplifiers and how to build basic electronic circuits. In the second experiment, they are introduced to the basics of programming and signal processing. Finally, in the third laboratory period, the students are asked to interface a computer to a real instrument and to acquire and process data.
109. Salin, Eric D.; Antler, Margaret; Bort, Guillaume. Evaluation of the simultaneous use of standard additions and internal standards calibration techniques for inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry (2004), 19(11), 1498-1500.
[abstract]
The use of internal standards combined with standard additions calibration for inductively coupled plasma mass spectrometry (ICP-MS) is discussed. Yttrium, rhodium, magnesium, cobalt, copper, nickel, silver, thallium, molybdenum and lead were analyzed in solutions of known composition with a 500 mg ml -1 Na matrix. Additionally, the Mg, Co, Y, Rh and Pb signals were used as internal standards for the other elements in the same matrix. Severe drift effects were simulated by drastically altering the liquid sample uptake rate. The signals were used to compare the results obtained using four different calibration methods: external standards, standard additions, internal standards and standard additions in combination with an internal standard. The average errors for external standards varied from 23 to 41% while the average errors for internal standards ranged from 1 to 71%. The error for standard additions was 45%. The use of standard additions with an internal standard produced an average error of 0.7-5%, suggesting that this is a powerful calibration technique.
108. Legrand, Melissa; Lam, Rebecca; Jensen-Fontaine, Madeleine; Salin, Eric D.; Chan, Hing Man. Direct detection of mercury in single human hair strands by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Journal of Analytical Atomic Spectrometry (2004), 19(10), 1287-1288.
[abstract]
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to detect mercury in single human hair strands. The most widely used technique for measuring mercury in hair samples is a wet digestion followed by cold vapor atomic absorption spectrometry (CV-AAS) detection. It was found that the level of mercury appeared to be decreasing further from the root end of the hair showing an increase in mercury concentration. It was also found that the use of signal ratios from LA-ICP-MS data appeared to be useful in determining changes in concentration over the length of hair strand.
107. Hamier, Jan; Salin, Eric D.. Design, construction and study of a continuously fed ohmically heated reactor for powdered solid sample digestion. Spectrochimica Acta, Part B: Atomic Spectroscopy (2004), 59B(9), 1451-1462.
[abstract]
The design, construction and testing of an ohmically heated graphite reactor for digestion of continuously fed powdered (<100-µm diameter) solid samples are discussed. The system operates in a continuous sample feed mode with a 100% power 3-kW duty cycle. The configuration provides a means of protecting the graphite reactor from contact with air and an efficient method of cooling the electrodes. Furthermore, the design includes a simple interface between the reactor and the powder feeder as well as between the reactor and the plasma. Experiments conducted on SO-4 Soil Certified Reference Material (CRM) as well as on 1646 Estuarine Sediment CRM demonstrated that a linear relationship existed between the integrated time-dependent signal and the net sample mass fed when the reactor's output was fed directly into an inductively coupled plasma atomic emission spectrometer (ICP-AES). The comparison between the experimental and theoretical composition ratios for both CRMs led to good agreement, between 0.27% and 11%, for elements certified in both CRMs. Absolute limits of detection of the order of 6-7 ng for Al, Ca and Fe were achieved. Under normal operating conditions, the power dissipated in the reactor was found to be of the order of 2-3 kW with corresponding temperatures of ~2400 to ~2700 K.
106. Lam, Rebecca; Salin, Eric D.. Analysis of pharmaceutical tablets by laser ablation inductively coupled plasma atomic emission spectrometry and mass spectrometry (LA-ICP-AES and LA-ICP-MS). Journal of Analytical Atomic Spectrometry (2004), 19(7), 938-940.
[abstract]
Laser ablation was studied with inductively coupled plasma atomic emission spectrometry (LA-ICP-AES) and with inductively coupled mass spectrometry (LA-ICP-MS) for the analysis of pharmaceutical tablets (10% and 20% Neusilin). For spot analysis with LA-ICP-AES, precision ranged from 12-31% relative standard deviation (RSD), but improved to 1-6% when ratios of signals were used. For continuous scanning, the precision ranged from 1-7% RSD. Weaker laser conditions required for ICP-MS gave precisions of 47-61% RSD (29% when signal ratios were used). Under unoptimized conditions, the detection limits for LA-ICP-AES of tablets were 70 µg g-1 for Al and 20 µg g -1 for Mg. The detection limits for LA-ICP-MS were 40 µg g -1 for Al and 6 µg g-1 for Mg. These results suggest that LA-ICP spectroscopy may find application in tablet analysis.
105. Tromp, John W.; Pomares, Mario; Alvarez-Prieto, Manuel; Cole, Amanda; Ying, Hai; Salin, Eric D.. Exploration of robust operating conditions in inductively coupled plasma mass spectrometry. Spectrochimica Acta, Part B: Atomic Spectroscopy (2003), 58B(11), 1927-1944.
[abstract]
'Robust' conditions, as defined by Mermet and co-workers for inductively coupled plasma (ICP)-atomic emission spectrometry, minimize matrix effects on analyte signals, and are obtained by increasing power and reducing nebulizer gas flow. In ICP-mass spectrometry (MS), it is known that reduced nebulizer gas flow usually leads to more robust conditions such that matrix effects are reduced. In this work, robust conditions for ICP-MS have been determined by optimizing for accuracy in the determination of analytes in a multi-element solution with various interferents (Al, Ba, Cs, K, Na), by varying power, nebulizer gas flow, sample introduction rate and ion lens voltage. The goal of the work was to determine which operating parameters were the most important in reducing matrix effects, and whether different interferents yielded the same robust conditions. Reduction in nebulizer gas flow and in sample input rate led to a significantly decreased interference, while an increase in power seemed to have a lesser effect. Once the other parameters had been adjusted to their robust values, there was no additional improvement in accuracy attainable by adjusting the ion lens voltage. The robust conditions were universal, since, for all the interferents and analytes studied, the optimum was found at the same operating conditions. One drawback to the use of robust conditions was the slightly reduced sensitivity; however, in the context of 'intelligent' instruments, the concept of 'robust conditions' is useful in many cases.
104. Salin, Eric D.; Ren, J. M. Direct filter vaporization with induction heating-electrothermal vaporization (IH-ETV) and a foam carbon surface. Journal of Analytical Atomic Spectrometry (2003), 18(8), 953-954.
[abstract]
An inductively heated electrothermal vaporizer (IH-ETV) sample introduction system was tested using a foam carbon surface with and without a standard air sampling filter employing ICP-AES excitation with a semiconductor based commercial detection system. Liquid detection limits using 10 µl injections were roughly comparable to those obtained using conventional nebulization on the same instrument. Mass detection limits ranged from 0.5 ng (Zn at 213.9 nm with a foam disk) to 20 ng (Pb at 220.4 nm with a filter). This performance suggests that IH-ETV vaporization of filters might find applicability in environmental air sampling studies.
103. Ren, J. M.; Rybak, Michael E.; Salin, Eric D.. Elimination of arcing in induction heating-electrothermal vaporization (IH-ETV) for sample introduction into inductively coupled plasmas. Journal of Analytical Atomic Spectrometry (2003), 18(5), 485-486.
[abstract]
Induction heating-electrothermal vaporization has been investigated for sample introduction to an inductively coupled plasma. Unfortunately, arcing takes place between a graphite sample cup and the surrounding glass chamber that is part of the set-up. This paper desccribes a method for the elimination of arcing.
102. Antler, Margaret; Ying, Hai; Burns, David H.; Salin, Eric D.. Sample diagnosis using indicator elements and non-analyte signals for inductively coupled plasma mass spectrometry. Spectrochimica Acta, Part B: Atomic Spectroscopy (2003), 58(5), 837-850.
[abstract]
A sample diagnosis procedure that uses both non-analyte and analyte signals to estimate matrix effects in inductively coupled plasma-mass spectrometry is presented. Non-analyte signals are those of background species in the plasma (e.g. N+, ArO+), and changes in these signals can indicate changes in plasma conditions. Matrix effects of Al, Ba, Cs, K and Na on 19 non-analyte signals and 15 element signals were monitored. Multiple linear regression was used to build the prediction models, using a genetic algorithm for objective feature selection. Non-analyte elemental signals and non-analyte signals were compared for diagnosing matrix effects, and both were found to be suitable for estimating matrix effects. Individual analyte matrix effect estimation was compared with the overall matrix effect prediction, and models used to diagnose overall matrix effects were more accurate than individual analyte models. In previous work [Spectrochim. Acta Part B 57 (2002) 277], we tested models for analytical decision making. The current models were tested in the same way, and were able to successfully diagnose matrix effects with at least an 80% success rate.
101. Huxter, Vanessa; Hamier, Jan; Salin, Eric D.. Tandem calibration methodology: dual nebulizer sample introduction for ICP-MS. Journal of Analytical Atomic Spectrometry (2003), 18(1), 71-75.
[abstract]
The application to inductively coupled plasma mass spectrometry (ICP-MS) of a calibration method called the TCM (tandem calibration method) is described. The TCM involves simultaneous introduction of sample and standard into the plasma by two nebulizers operated in parallel. Figures of merit were determined by comparing the results obtained with those produced using the method of standard additions and external standard calibration was used as a probe of the severity of the matrix effect induced. The test solutions in this study contained Cu, Y, Pt and Pb as analytes and 10 mM Ba and 35 mM Na as matrix effect generators. Classical standard addition verified the validity of the TCM and the two methods were shown to be statistically equivalent. The precision of the results obtained was limited by the noise of the sample introduction device (about 4% RSD on difficult samples versus roughly 1% on clean standards), while the accuracy was only slightly limited by the short and long term stability of the arrangement, typically around 2% relative error. The method was easy to implement on existing equipment, inexpensive and potentially suited to automation.
100. Skinner, Cameron D.; Salin, Eric D.. Preconcentration and adsorption of metal chelates with analysis by direct sample insertion inductively coupled plasma atomic emission spectrometry. Journal of Analytical Atomic Spectrometry (2003), 18(5), 495-500.
[abstract]
An automated preconcentration system that utilizes adsorption of 8-hydroxyquinoline (8-HQ) metal chelates onto a silica-C18 column has been evaluated. The metal chelates are desorbed with methanol and sprayed into an inductively heated graphite direct sample insertion cup. In this manner the organic solvent and much of the 8-HQ is removed and does not appear to cause interferences in the plasma. The detection limits of the current system are 8, 30, 60, 10, 9 and 40 parts per trillion for Cd, Cu, Fe, Mn, Pb and Zn, respectively, utilizing the reagents as purchased. Instrumental detection limits of 1, 0.2, 90, 0.3, 2 and 10 ppt for the same elements were calculated assuming that blank contamination can be eliminated.
99. Filion, Julie; Munz, Richard J.; Salin, Eric D.. Molecular emission spectroscopy as a potential diagnostic tool in plasma-assisted incineration. Applied Spectroscopy (2002), 56(4), 449-454.
[abstract]
This paper reports on a simple analytical procedure used to demonstrate the technical feasibility of adaptive plasma-assisted incineration. APAI is a novel concept that addresses current difficulties in the treatment of hazardous organic waste. It features continual optimization of a plasma afterburner's operating conditions for cost-effective destruction of persistent contaminants under variable feed loads. Hence, on-line composition monitoring is a key element of the process. A diagnostic method was specifically developed for an experimental model system that required optical measurements from the jet of a 25-kW induction plasma torch. The method used photodiode array detection of visible emission from the Swan band system of C2 to track the destruction of organic compounds. This rapid, simple, and inexpensive procedure proved adequate for demonstration purposes.
98. Ying, Hai; Antler, Margaret; Tromp, John W.; Salin, Eric D., Sample diagnosis using non-analyte signals for inductively coupled plasma mass spectrometry. Spectrochimica Acta, Part B: Atomic Spectroscopy (2002), 57B(2), 277-290.
[abstract]
A sample diagnosis procedure that uses non-analyte signals to predict matrix effects in inductively coupled plasma-mass spectrometry (ICP-MS) is presented. Non-analyte signals are those of other species which are present in the plasma (e.g. Ar2+), and monitoring them can indicate changes in the instrument or sample. Matrix effects of Na, Al, K, Cs, and Ba on 19 non-analyte signals were studied. Non-analyte signals changed significantly in the presence of the matrices. The heavier matrices, Cs and Ba, caused more interference. Stagewise regression was applied to build prediction models. The results showed that matrix effects caused by matrices of various concentrations could be predicted, with the predictions of the model well correlated with the test experimental results. In previous work, we introduced a total interference level (TIL) model, which predicted interferences based on previous experiments, and tested it in terms of analytical decision making. The current model is tested in the same way, and gave excellent results. In terms of guaranteeing a desired accuracy, the predictions were at least 80% correct for test solutions with overall matrix effects that varied from 10 to 50%. The key prediction factors were also determined. The main conclusion of this study was that the presence of matrix effects could be detected by online monitoring of only non-analyte signals.
97. Rybak, Michael E.; Salin, Eric D.. Direct determination of metals in soils and sediments by induction heating-electrothermal vaporization (IH-ETV) inductively coupled plasma-optical emission spectrometry (ICP-OES). Applied Spectroscopy (2001), 55(7), 816-821.
[abstract]
The application of an induction heating (IH) electrothermal vaporization (ETV) sample introduction arrangement for the determination of As, Cd, Cu, Mn, Pb, and Zn in soils and sediments by inductively coupled plasma-optical emission spectrometry (ICP-OES) is presented. Samples were deposited either directly as a solid or by means of slurry sampling into graphite cups that were then positioned in a radio-frequency (RF)-field and vaporized in a carrier flow of 15% (v/v) SF6-Ar. Four certified reference materials (CRMs) were examined: two soil samples - SRM 2710 and SRM 2711 (NIST); and two marine sediments - MESS-2 and PACS-2 (NRC Canada). In general, sample delivery was simpler and observed signal precision was better with slurry sampling when compared to the analysis of the solid directly, with peak area RSDs ranging from 4-16% (n = 6). Plots of intensity vs. certified concentration for the four CRMs were linear with log-log slopes of 0.98-1.02 and r2 values = 0.995 for As, Cu, Pb, and Zn. Recoveries of 80-105% were achieved for the above elements in SRM 2711 by using an external standards curve constructed from the 3 remaining CRMs. Aqueous standard solutions were used for the analysis of all 4 CRMs by standard additions, resulting in recoveries ranging from 54-139% (average recovery of (101 ± 15)%) across all six determined elements in all four samples.
96. Filion, Julie; Munz, Richard J.; Salin, Eric D.. A feasibility study of adaptive plasma-assisted incineration, part 1: demonstration on a laboratory model system. Canadian Journal of Chemical Engineering (2001), 79(4), 612-617.
[abstract]
The use of a thermal plasma afterburner in hazardous waste incineration could prevent the formation of toxic organochlorine pollutants. The present work demonstrated cost-optimal adaptive operation of a laboratory model system composed of an induction plasma jet with optical emission diagnostic tools. Input settings (plasma power and oxygen content) were continually adjusted in response to on-line spectroscopic analysis of the product gas. This adaptive strategy allowed cost-effective destruction of organic contaminants under a variable feed load. The system was able to reach and maintain a target level of destruction efficiency using optimal combinations of input settings.
95. Filion, Julie; Munz, Richard J.; Salin, Eric D.. A feasibility study of adaptive plasma-assisted incineration, part 2: techno-economic potential assessment. Canadian Journal of Chemical Engineering (2001), 79(4), 618-625.
[abstract]
This work assesses the techno-economic potential of using an adaptive d.c. thermal plasma afterburner in hazardous waste incineration. Preliminary cost estimates were developed for soil incineration, soil desorption and liquid waste incineration. In general, the annual operating costs of plasma-assisted processes (including depreciation of capital) exceed the costs of fuel combustion processes by 50%. However, a qualitative examination of environmental, legal and technical factors suggests that plasma treatment offers significant benefits in terms of effectiveness, safety and regulatory compliance.
94. Abbyad, Paul; Tromp, John; Lam, Joseph; Salin, Eric. Optimization of the technique of standard additions for inductively coupled plasma mass spectrometry. Journal of Analytical Atomic Spectrometry (2001), 16(5), 464-469.
[abstract]
The use of standard additions in the presence of instrument drift and the optimum size of the added spike relative to the unknown analyte concentrations have been investigated for ICP-MS. In particular, a bracket approach, where the spiked sample is measured between two different measurements of the sample, has been investigated. The average of the two sample measurements is used in the standard additions formula to estimate concentration. Several multi-element analyte solutions with single element matrices (Na, Cs, Ba), were analyzed using both the bracket approach and regular standard additions. It was found that the bracket approach led to better results where drift was significant. In addition, optimum spike size was investigated. Simple models predict that determinations would be more precise with larger spikes if the instrument response was linear and RSD was constant. These results show that while the use of larger spikes (from 7 to 50 the unknown concentration) did not yield the better precision predicted by the models, the precision was no worse than for spikes of size equal to the unknown concentration. The Autonomous Instrument project is an approach to the automation of ICP-MS based on choosing an appropriate analytical calibration methodology for an unknown sample. The method of standard additions is the most accurate analytical methodology considered by the Autonomous Instrument. These results have implications for the Autonomous Instrument, suggesting that bracket standard additions should be considered the best method, followed by regular standard additions. In addition, the spike size results imply that in automatic determination, the long linear range of ICP-MS allows the addition of large analyte spikes with minimal prior knowledge of the sample.
93. Ying, Hai; Tromp, John W.; Antler, Margaret; Salin, Eric D.. Pattern recognition using elemental composition for analytical methodology decision making in atomic spectroscopy. Journal of Analytical Atomic Spectrometry (2001), 16(10), 1135-1141.
[abstract]
Three main classification methods, kNN, Bayesian, and C4.5 inductive learning were investigated for their ability to differentiate types of either aluminium or steel alloys. Simulation experiments were performed with two generated test data sets to evaluate their potential for classifying samples based on elemental compositions. The first test set had normally distributed errors of 25% RSD. This data set simulated results of a preliminary scan of semi-quantitative accuracy to be used for selection of a calibration methodology. The second test set had 5% RSD and simulated results of a quantitative analysis, where the identity of the sample was to be determined (identification). The Bayesian method provided the best results with prediction accuracy rates of 89.8% for the first goal (methodology selection) and 100% for the second (identification) in Al alloys. Steel alloys were also classified best with the Bayesian method, with 96.7% and 100% accuracy, respectively. A detailed flow chart for sample recognition is proposed, which optimizes both prediction accuracy and calculation speed.
92. Rybak, M. E.; Salin, E. D.. Development and characterization of induction heating-electrothermal vaporization (IH-ETV) sample introduction for inductively coupled plasma spectrometry. Spectrochimica Acta, Part B: Atomic Spectroscopy (2001), 56B(3), 289-307.
[abstract]
A general study of performance attributes was conducted for a prototypical electrothermal vaporization (ETV) sample introduction system, in which induction heating (IH) was used to facilitate the drying, pyrolysis, and vaporization of samples from long, undercut graphite cup probes in a radio-frequency (RF) induction field. In the first part of this study, experiments were carried out to determine the heating characteristics and temperature control aspects of an IH-ETV arrangement. Using a remote-sensing infrared thermocouple, it was determined that a 3/8-inch (9.53-mm) outer diameter graphite cup sample probe could be heated to a maximum temperature of 1860°C in the induction field of the IH-ETV under full forward power (1.5 kW). The IH-ETV device was found to have a rapid heating response (1/e time-constant of 2.0±0.2 s) that was independent of the initial/final temperatures chosen. Linear temperature control was possible by regulating either the DC voltage applied to the plate or the current flowing to the grid of the RF generator oscillator tube. The second part of this work consisted of studies to establish benchmarks, such as limits of detection (LOD) with inductively coupled plasma optical emission spectrometry (ICP-OES) and transport efficiency for analyte vaporization under several x-Ar mixed gas atmospheres [where x = 15% N2, 10% O2, HCl (sparged), or 15% SF6 (v/v)]. In general, reproducible transient signals with evolution times of 5-15 s were seen for the vaporization of most elements studied, with peak area intensity and reproducibility generally being the best with SF6-Ar. A 10-fold increase in transport efficiency was seen for refractory carbide-forming analytes (Cr, V) when vaporization was conducted in a halogenous (x = HCl, SF6) versus non-halogenous (x = N2, O2) environment, with a two-fold improvement being observed for most other non-refractory elements (Cd, Cu, Fe, Mn, Ni, Pb, Zn). The transport of arsenic proved to be a special case unto itself, with its transport efficiency increasing to 90% when vaporized in the presence of SF6 (a three-fold improvement over all other carrier mixtures) due to the formation of volatile AsF5. Using the concept of transport-independent analyte sensitivity, the introduction of the aforementioned x-Ar mixtures into the center channel of the plasma appeared to not have any appreciable effect on plasma excitation conditions, with N2 being the only exception (a 70% reduction in transport-independent sensitivity was observed). Detection limits ranged from 0.08 to 70 ng absolute and were highly dependent on the analyte studied and the vaporization atmosphere used. Based on the above information, the feasibility of an induction heating arrangement for thermal sample introduction was evaluated, with recommendations being made for the future design of IH-ETV instrumentation.
91. Tromp, John W.; Cole, Amanda; Ying, Hai; Salin, Eric D.. Prediction of multiple matrix interferences in inductively coupled plasma mass spectrometry. Applied Spectroscopy (2001), 55(5), 611-620.
[abstract]
Matrix effects for pairs of interferents (Al, Na, K, Ba, and Cs) were investigated and compared to predictions of the amount of interference determined by single interferent experiments in order to test a model called the total interference level (TIL), which assumes that the effects of different interferents add linearly. The TIL model is part of an Autonomous Instrument and is designed to indicate when a simple default calibration, such as external calibration or internal standardization, is inadequate for the desired accuracy of analysis. The performance of the TIL model was examined in terms of a daily calibration basis, which should be more accurate, and an occasional calibration basis, which is more convenient, considering simple external standardization and internal standardization as the techniques to be tested for desired accuracy. The results are encouraging for multiple interferences and show that the TIL model can serve a useful function in predicting calibration errors, even given the presence of instrument drift on ICP-MS.
90. Rybak, Michael E., Hatsis, Panos, Thurbide, Kevin, Salin, Eric D., 2001, Rapid analysis of metals in wood pulp by direct sample insertion - inductively coupled plasma optical emission spectrometry, TAPPI, 84(1) Jan, 1-7.
[abstract]
The analysis of metals in wood pulp is demonstrated using the method of direct sample insertion (DSI) with inductively coupled plasma-optical emission spectrometry (ICP-OES). It is shown that this method is much more rapid than the standard digestion method, and produces adequate precision and accuracy.
89. Rybak , Michael E., Salin, Eric D., 2000, Closed-system trapping method for the direct determination of transport efficiency in electrothermal vaporization sample introduction, Journal of Analytical Atomic Spectrometry, 15(7), 883-887.
[abstract]
A novel closed-system for the direct determination of analyte transport efficiency in electrothermal vaporization (ETV) sample introduction is described. A commercially available gas-sampling bag filled with 100 ml of 10% HNO3 was connected to the exhaust of an ETV system and used to collect and seal the product of an electrothermal vaporization event. The bag was then manually agitated, and its liquid contents decanted and analyzed by solution nebulization ICP-MS. Analyte transport efficiency values were found to be in statistical agreement with those determined by a reference method on the same ETV system for a variety of volatile (As, Cd, Mn, Pb), involatile (Cu, Ni) and refractory carbide forming (V) elements. This simple experimental setup captures all of the analyte in a single solution, with the closed-system element of its design ensuring that this is done quantitatively. Absolute detection limits for most elements were of the order of 0.1-10 ng absolute for the technique, making it well suited for analyte masses typically vaporized in ETV-ICP-OES. The relative merits of using this type of setup for the determination of analyte transport efficiency in ETV sample introduction, along with experimental considerations, are described.
88. Tromp, John W., Tremblay, Raphael, Mermet , Jean-Michel and Salin, Eric D., 2000, Matrix interference diagnostics for the automation of Inductive Coupled Plasma Mass Spectrometry (ICP-MS), J. Anal. At. Spectrom., 15(6), 617-625.
[abstract]
Matrix interferences in inductively coupled plasma mass spectrometry (ICP-MS) were examined to extend the total interference level (TIL) concept from ICP-AES. The TIL model is based on measurements with different interferents to determine a set of interference coefficients. Interference is assumed to be linear with interferent concentration, since that assumption allows determination of the model parameters with the fewest experiments. The TIL model was designed to indicate when a simple external standards calibration method is inadequate for a desired level of analytical accuracy and was also tested on a simple form of internal standards. The TIL concept was tested in both an initial calibration and a daily calibration mode on the interferents Na, K, Al, Ba and Cs and works well for situations where external standards are used, recommending an inaccurate method for only 3% of cases where 10% accuracy was desired. The TIL model also works well with the very different calibration technique of internal standards, recommending an inaccurate method for 9% of cases where 10% accuracy was desired.
87. Villanueva, Margarita, Catasus Miguel, Pomares, Mario, Salin, Eric D., 2000, Study of Mixed-Matrix Effects Induced by Ca and Mg in ICP-AES, J. Anal. At. Spectrom., 15(7),883-887.
[abstract]
The combined matrix effects produced by the simultaneous presence of C and Mg were investigated. The description was performed using a 22 factorial design. For B, Ba, Co, Fe, Mn, Si and Sr, the total effect is the same as the sum of the individuals, the rest of the analytes exhibited a combined effect that is smaller (Cu, Cd and Ni) or bigger (Cr) than the sum of the single ones. A multiple linear regression was employed to correct for matrix effects. The effectiveness of the method was also tested in experimental conditions when the variation of analyte line intensities is the result of the superposition, in different degrees, of spectral interferences and matrix effects. Average deviations from the expected values in the range of 61-6% were reduced to 4.8-0.5% after the application of the correction method.
86. Ying, H.; Murphy, J.; Tromp, J. W.; Mermet, J.-M.; Salin, E. D, 2000,. Warning diagnostics for inductively coupled plasma-mass spectrometry. Spectrochim. Acta, Part B 55B(4), 311-326.
[abstract]
The performance of an inductively coupled plasma mass spectrometer is substantially impacted by changes in radio frequency power, nebulizer gas flow, and sample liquid flow. A simple diagnostic procedure has been developed to automatically ensure that the quality of results is not compromised by system degradation. The diagnosis procedure was studied in two different stages of instrument operation: the normal operating stage and the warm-up stage. For normal operating stage monitoring, a decision tree was derived with the C4.5 induction engine applied to Ar-based signals allowing instrument performance to be classified as either normal or abnormal. Abnormal signals were further classified as to their probable cause. Signals present in both deionized water and 0.5% nitric acid spectra are sufficient for diagnosis with an accuracy of 96.0% and 94.0%, respectively, allowing the use of `blank' solutions to monitor instrument performance. For the warm-up stage diagnosis, a standard solution containing Li, In, Ba and Bi, was used. Stepwise regression was applied as the key factor filter while partial least square (PLS) was adapted to be the classifier. In addition to the modeling test, the importance of the intensities and intensity ratios of different masses was studied. By eliminating the standard element signals from the model, the possibility of using water/nitric acid as test solutions was also studied. The overall prediction accuracy for the warm-up stage is approximately 92% using the standard solution or either the water or nitric acid type blank solutions.
85. Rybak, M.E.; Hatsis, P.; Thurbide, K.; Salin, E.D., 1999, Rapid Determination of Cu, Fe, Mg, Mn, and Zn in wood Pulps by Direct Sample Insertion Inductively Coupled Plasma Optical Emission Spectrometry using a Pyrolytically Coated Graphite Sample Probe, J. Anal. At. Spectrom., (14)11, 1715.
[abstract]
A rapid method for screening wood pulp samples by direct sample insertion-inductively coupled plasma-optical emission spectrometry (DSI-ICP-OES) is described. Solid wood pulp samples were introduced directly into an inductively coupled plasma, using a pyrolyrically coated graphite DSI sample probe, after in situ chemical treatment with HCl and NaF. Drying and ashing steps were performed by inductively heating the sample probe in the ICP coil prior to plasma ignition. The analysis time of the method from sample acquisition to analysis was of the order of several minutes per sample, as compared to several hours when conventional dissolution methods are used. Agreement with reference values for wood pulp samples ranged from 3.4-16% (absolute) for high-concentration analytes (Mg, Mn) and 1.7-50% (absolute) for low-concentration ones (Cu, Fe, Zn) using external standards. Precision ranged from 6-50% RSD and was highly dependent on the element and pulp sample studied. Absolute detection limits for the method were of the range of 50-1000 pg, translating into relative detection limits of 20-400 ppb based on a 2.5 mg pulp sample. The merits of using DSI-ICP-OES for the direct analysis of wood pulps, and of using a pyrolytically coated graphite probe for this type of application, are discussed.
84. Sartoros, Christine; Salin, Eric D., 1999, Automatic selection of internal standards in inductively coupled plasma-mass spectrometry Spectrochim. Acta Part B: 54:11:1557-1571.
[abstract]
The automatic selection of internal standards in inductively coupled plasma-mass spectrometry was performed using a cluster analysis algorithm. The samples contained 25 analytes, spanning the atomic mass and ionization potential ranges, and a single interfering element. The interferents examined were Na, Mg, K, Zn, Ba, and Pb. The cluster analysis algorithm used kinetic energy, ionization potential, oxide bond strength, hydride bond strength, and electronegativity, to group the analytes. These variables were weighted differently in the various matrices. The performance of the clustering method and selection of internal standards was good for most analytes in the various
83. Hamier, Jan; Salin, Eric D., 1998, Towards Steady-State Direct Solid Sample Analysis by Inductively Coupled Plasma Atomic Emission Spectrometry: Qualitative Evaluation of an Intraplasmic Powdered Sample Digester, Spectrochim. Acta, Part B, 53B(9), 1303-1315.
[abstract]
A new type of reactor designed for continuous halogen-assisted digestion and analysis of powdered samples was evaluated. Two different halogenating gas introduction methods were tested, as well as the use of an internal baffle to increase the residence time of the solids inside the reactor. Studies were carried out on Al2O3 and CuO as model compounds for optimization of the reactor's parameters, such as the carrier gas flow, the fraction of halogenating gas and the feed rate, using Freon-12 as the halogenating gas. A qualitative study of a pseudo fluidized bed reactor (PFBR) was also performed on a soil sample certified reference material (SO-4). The internal gas flow rate had to be kept to an absolute minimum in order to minimize cooling of the PFBR's inner walls. Pre-mixing of the halogenating reagent into the solid aerosol carrier resulted in a much more efficient reaction than separate flow introduction. The use of a baffle drastically improved the digestion efficiency by virtue of an increased solid residence time. The argon plasma did not have a sufficiently high heat transfer capability to ensure proper operation of the PFBR under continuous sample loading. The porosity of the graphite used for the PFBR construction caused some tailing and memory effects due to analyte seepage into the reactor's walls.
82. Skinner, Cameron D.; Cazagou, Murielle; Blaise, Joanne; Salin, Eric D., 1999, Direct insertion of trace metals preconcentrated on activated charcoal into an inductively coupled plasma, Appl. Spectrosc., 53(2), 191-196.
[abstract]
Trace metals have been concentrated onto activated charcoal by using oxalic acid, iminodiacetic acid, and 8-hydroxyquinoline. The charcoal was directly analyzed in an ICP by placing several particles in a direct sample insertion (DSI) cup, or fabricating a DSI probe with an activated charcoal cap. Detection limits in the tens to hundreds of parts per trillion were found for Pb, Cd, Zn, and Cu. The recovery for Cu was 2-5% but may be improved by reactivation of the plasma-cleaned charcoal. Cleaning the charcoal, derived from wood, in the plasma prior to adsorption was necessary to remove trace metals.
81. Alary, Jean-Francois; Salin, Eric D., 1998, Quantitation of Water and Plasma Diagnosis for Electrothermal Vaporization-Inductively Coupled Plasma - Mass Spectrometry: the Use of Argon and Argide Polyatomics as Probing Species, Spectrochim. Acta, Part B, 53B(12), 1705-1721.
[abstract]
The water content of the carrier flow originating from an electrothermal vaporization unit (ETV) attached to an inductively coupled plasma mass spectrometer was monitored by following the argon hydride ion (ArH+) at m/z = 37. The goal was to measure the water expelled by the ETV at sample vaporization and evaluate the influence of this parameter on the ion-generation efficiency. Linear responses from the argon hydride were obtained when the water loading in the plasma injector flow was increased from 0 to 3.3 mg/min. Other argides and water-derived species (Ar+, Ar2+ and O2+) were also monitored simultaneously and the effects from operating parameters have been calculated for each species. The magnitude of these effects can eventually be used as diagnosis tools. It was also found that signals for zinc, copper, lead, antimony and arsenic were greatly influenced by slight variations in water loading at low water levels. These signal fluctuations are greatly attenuated and transients' shapes restored by convoluting each element transient with the ArH+ or Ar2+ curves that were recorded simultaneously. Envisioned applications that would benefit from a water-enhanced signal include spray electrothermal vaporization, direct sample insertion and laser ablation for inductively coupled plasma-mass spectrometry. The argon dimer Ar2+ seems more appropriate for making the correction since it provides a direct insight on the plasma temperature and provides a robust signal.
80. Goltz, Douglas M.; Skinner, Cameron D.; Salin, Eric D., 1998, Sample Introduction for Inductively Coupled Plasma-Atomic Emission Spectrometry using an Inductively Heated Vaporizer, Spectrochim. Acta, Part B, 53B(6-8), 1139-1147.
[abstract]
A sample introduction system for inductively coupled plasmas (ICPs) which utilizes an induction coil for vaporizing analyte has been developed. This device uses HCl(g) in the carrier gas to prevent arcing in the induction furnace. Adding HCl has the additional benefit of acting as a physical carrier which can enhance analyte transport and allow the vaporization of relatively non-volatile elements. Experiments were carried out to investigate some of the performance characteristics of this vaporizer. Absolute detection limits using inductively coupled plasma atomic emission spectrometry (ICP-AES) for a number of elements ranged from 1.5 to 30 ng corresponding to relative detection limits which ranged from 0.04 to 0.7 ng ml-1. Compared with solution nebulization, improvements in detection limits for these elements was 2-3 orders of magnitude. Analysis of Zn, Mn and Cu in a number of reference samples, including river water, lobster tissue and river sediment, demonstrated the applicability of this vaporizer for a variety of matrices.
79. Michael Rybak, Eric D. Salin, Pyrolytically Coated Graphite Direct Sample Insertion Probe for Inductively Coupled Plasma Spectrometry, J. Anal. At. Spectrom, 13(8), 707-713 ).
[abstract]
The pyrolytic coating of a graphite cup direct sample insertion (DSI) probe for inductively coupled plasma spectrometry is described. Deposition of a pyrolytic coating on the inside walls of the DSI cup was achieved by heating the device in a 2 kW argon plasma while directing a gaseous mixture of 10% methane in argon (v/v) to the graphite cup interior. A narrow channel hollowed into the stem of the graphite cup facilitated introduction of the methane-argon mixture. A factorial study revealed that the procedure generated optimum results when the coating was applied for at least 10 min at a flow rate of 500 ml min-1. Peak area and height reproducibility improvements for Cd, Cu, Mg, Pb and Zn ranged from 1.7-3.4 and 2.1-6.7% RSD, respectively, when a pyrolytically coated DSI cup was used, versus 3-7 and 5-12% RSD when no coating was used. The abatement of multiple peaking and an increase in transient signal intensity was observed for all elements except Cu, translating into roughly a two-fold improvement in peak height limit of detection when a pyrolytically coated DSI probe is used. Scanning electron microscopy and Raman spectroscopy of the DSI cup interior confirm the deposition of a uniform pyrolytic phase of high crystalline order on the DSI cup.
78. Robin Rattray, David H. Burns, Eric D. Salin, , Peak Fitting and Deconvolution for Determination of the Impulse Response Function of the Sample Introduction System in Flow Injection Inductively Coupled Plasma Spectrometry. Appl. Spectrosc. (1999), 53(12), 1642-1645.
[abstract]
A technique for determining the impulse response function for an inductively coupled plasma atomic emission spectrometry sample introduction system is demonstrated. The input response function may then be useful for the determination of outputs, and consequently the performances, of flow injection or other sample treatment systems, which precede the sample introduction system. In a procedure to generate a known input response, a bolus of analyte was proceeded and followed by an air bubble, which reduced dispersion to a minimum. The impulse response function was determined and used to deconvolute other inputs of known concentration and dispersion. The deconvolution of the outputs using the impulse response function returned the expected result, indicating that the technique and impulse response function were correct. When used with an unsegmented traditional flow injection sample introduction valve, the system demonstrated clearly that significant dispersion takes place even in very compact introduction arrangements.
77. Guy Légère, Eric D. Salin, Design and operation of a capsule-based microwave digestion system. Anal. Chem. (1998), 70(23), 5029-5036.
[abstract]
A high-pressure microwave digestion system has been designed based on the concept of using large-bore tubes as digestion vessels and capsules as a vehicle for sample introduction. Many of the design aspects are dictated by the use of a relatively large (8.4 mm o.d., 25 mm long) capsule, which in turn dictates the inner tube dimensions. A variety of materials were studied for use as the tubing material. PFA was selected as the best material for a demonstration arrangement. The cycle of operation involves insertion of the capsule by a flexible rod followed by addition of digestion reagent and then a heating/cooling/venting cycle for removal of gases. When the digestion is completed, the system removes the liquid with the same flexible rod and then cleans itself. The system is highly automated with computer-controlled venting, cooling, and reagent addition. Data indicate that performance is similar to that expected of a conventional microwave oven operated at the same temperatures.
76. Jan Hamier, Eric Dunbar Salin, Tandem Calibration Methodology: Dual Nebulizer Sample Introduction for ICP-AES, J. Anal. At. Spectrom., 13, 1998, 497-505.
[abstract]
A calibration method based on the simultaneous introduction of sample and standard into the plasma by two independent devices is described. In this specific implementation, two nebulizers are linked to the ICP by a Y-shaped tube. Figures of merit were determined by comparing the results obtained with those produced using the method of external calibration. 'Difficult samples' containing matrices of C, Na, Al or K in concentrations ranging from 1000 to 10 000 ppm were used to provide matrices that produced significant errors when used with external calibration. The test solutions used for this study were mixtures of some of the following elements: Al, Cu, Mg, Fe, Ni, Pb and Zn in one of the matrices described previously. The comparison between the proposed tandem calibration method (TCM) and the method of external calibration clearly indicates that the TCM appears to be a valid alternative to traditional calibration methods, such as standard additions, matrix-matching and internal standards, that are commonly used when external calibration fails to give valid results for 'difficult samples' introduced into the ICP by means of a nebulizer. Improvement factors in accuracy based on the ratio of the relative error were, on average, of the order of 4 and, in some cases, well in excess of a full order of magnitude. For liquid samples, the precision of the results obtained by the proposed method was limited mainly by the noise of the sample introduction device (about 5% RSD on 'difficult samples' versus roughly 1% on clean standards) while the accuracy was limited by both the short- and long-term stability of the arrangement, typically around 7% relative error. In addition, the method was found to be easy to implement on existing equipment, inexpensive and potentially well suited for automation.
75. Jan Hamier and Eric Salin, Digestion efficiency study of an intraplasmic reactor for in-situ, halogen assisted direct solid sample digestion by Inductively Coupled Plasma Atomic Emission Spectroscopy. Spectrochim. Acta. B, 53, 1998, 621-632.
[abstract]
A new type of intraplasmic reactor designed for in-situ, batch digestion of refractory solid samples, the Modified Direct Sample Introduction (MDSI) reactor, is presented qualitatively evaluated with CH3Cl, Cl2 and Freon-12 as gaseous halogenating reagents. A comparison of the digestion capabilities of MDSI and CH3Cl or Freon-12 assisted electrothermal vaporization is also presented. The refractory model compounds used were Al2O3 and SiO2, which were deposited inside the reactor as 10 µl of a 1% m/m slurry. A soil sample SO-3 CRM was also used to evaluate the detection limits, which were found to be in the ppb range for sensitive lines (Cu and Pb) and in the ppm range for less sensitive lines (Al; Fe, Si and Zn). The results obtained indicate that the MDSI reactor design rapidly achieved a sufficiently high temperature for quantitative vaporization of the samples. The study of the various halogenating reagents show that (1) the presence of carbon in the halogenating reagent acts as a reducing agent for the oxides and also forms a protective pyrolitic graphite coating on the reactor's inner walls, thereby reducing analyte permeation into those walls and (2) the ideal gaseous halogenating reagent must exhibit a good thermal stability to intermediate temperatures (approximately 200 °C) to avoid premature decomposition. The reactive intermediates must also be thermally stable to avoid formation of soot that may plug the reactor and reduce the vaporization. Of all reagents tested, Freon-12 remains the reagent of choice for in-situ digestion of refractory solids.
74. Christine Sartoros, Douglas M. Goltz and Eric D. Salin, Program Considerations for Simplex Optimization of Ion Lenses in ICP-MS. Appl. Spectrosc.,52, 1998, 643-648.
[abstract]
The performance of an inductively coupled plasma mass spectrom-eter (ICP-MS) is dependent on the ion optic bias potentials. A discussion of the multielement optimization of the ICP-MS ion optics bias potentials using a Simplex algorithm is presented. Three objective functions were tested: a function developed by Leary; the combined ratio method (CRM); and the Euclidean distance from multicriteria target vector optimization. Both the Leary and the target vector optimization's performances were comparable, whereas the CRM optimizations placed an emphasis on obtaining similar signal intensities. Experiments determined that an initial Simplex starting size of 20% of the parameter space was optimal. A method for the selection of an appropriate target vector by predicting analyte signal intensity was also investigated. Signal intensities for all elements could be predicted with an acceptable margin of error (10-30%), provided that the same conditions were used. Comparisons of optimizations using a single mid-mass element vs. multielement optimizations revealed that the multielement approach is only slightly better. If the analyst wished to optimize lens settings to favor heavy or light elements, then an average mass was better than a mid-mass optimization.
73. C. Sartoros, Eric D. Salin, Inductively Coupled Plasma-Atomic Emission Spectrometer Warning Diagnosis Procedure Using Blank Solution Data. Spectrochim. Acta. B, 53, 1998, 741-750.
[abstract]
Lines available while running a blank solution were used to monitor the analytical performance of an inductively coupled plasma atomic emission spectrometry (ICP-AES) system in real time. Using H and Ar lines and their signal-to-background ratios (SBRs), simple rules in the form of a prediction table were developed by inspection of the data. These rules could be used for predicting changes in radio-frequency power, carrier gas flow rates, and sample introduction rate. The performance of the prediction table was good but not excellent. Another set of rules in the form of a decision tree was developed in an automated fashion using the C4.5 induction engine. The performance of the decision tree was superior to that of the prediction table. It appears that blank spectral information can be used to predict with over 90% accuracy when an ICP-AES is breaking down. However this is not as definitive at identifying the exact fault as some more exhaustive approaches involving the use of standard solutions.
72. Douglas M. Goltz, Eric D. Salin, 1997, Inductively Heated Vaporizer for Inductively Coupled Mass Spectrometry, J. Anal. At. Spectrom., 12, 1175-1180.
[abstract]
An inductively heated vaporizer (IHV) was used to introduce analyte, as a dry aerosol, into an ICP-MS instrument. Sample volumes of 5-300 µl were pipetted into a graphite cup, which was then placed in the induction coil of the IHV to dry, pyrolyze and vaporize the analytes of interest. A small amount Of N2, added to the Ar carrier flow, was used to prevent arcing between the graphite cup and the induction coil of the induction furnace. Experimental parameters such as Ar carrier flow, rf power and torch position were optimized by placing a small crystal of I2 in the graphite cup of the IHV and maximizing the 127I+ signal. Linearity of the calibration graphs improved and integrated signal intensity increased with increased mass of analyte deposited in the graphite cup. Limits of detection (LODs) in the range 3-100 pg ml-1 were achieved for Ag, Pb, Cd, Tl and Zn. When compared with solution nebulization, these LODs represent an improvement of 3- to 30-fold depending on the element.
71. Wayne A. Branagh, Christine Sartoros, Eric D. Salin, 1997, Towards Automatic Selection of Calibration Techniques for ICP-AES Can. Journal of Analytical Sciences and Spectroscopy, 42(130-141).
[abstract]
Automatic selection of a calibration technique is an important aspect for an instrument that will be expected to analyze novel samples completely without human intervention. The development of a system for calibration methodol. selection for ICP-AES is presented. The most common calibration techniques are discussed, their performances are compared and rules for their application to samples were generated. The selection of calibration technique was made for the 12 elements in a test universe. Several criteria were used in the selection: the approx. analyte and matrix concns. and the values of several economic constraints imposed by the user. These constraints include: the time/cost of an anal.; the sample vol. required for the anal. and the desired level of accuracy. A procedure for weighting each factor's relative importance is given and the inclusion of addnl. constraints is discussed. After eliminating all calibration techniques whose performance is inadequate, the remaining ones are ranked by how well they meet the user's constraints. The performance of the computer in selecting methodologies is evaluated by comparing its choices against those made by human analysts.
70. Cameron D. Skinner, Eric D. Salin, 1997, Images of the Direct Sample Insertion Process, J. Anal. At. Spectrom., 12, 1131-1138.
[abstract]
An inductively coupled plasma was imaged with a charge coupled device camera through interference filters during direct sample insertion. Images were acquired throughout the insertion and revealed how the analyte behaves in the plasma. Graphite cups, graphite tubes and wire loops were used as sample carrying probes. The diameter of the graphite cup has a dramatic effect on the plasma and calcium emission. Narrower cups disturb the plasma the least and keep the calcium within the center of the plasma. The use of a carrier gas through a graphite tube and hollow stem cup shows that a darker central channel is established. The use of a central gas in combination with Freon-12 yields a performance comparable to that of wire loops. In the case of a deep and narrow graphite cup the analyte appears to emerge into the plasma along the walls of the cup.
69. Cameron Skinner, Eric D. Salin,1997, Axial Viewing and Modified Cup Design for Direct Sample Insertion Inductively Coupled Plasma Atomic Emission Spectrometry, J. Anal. At. Spectrom, 12, 725-732.
[abstract]
Axial viewing generally provides an advantage over lateral viewing of the plasma for direct sample insertion. The signal change is element-specific and has produced detection limit improvements as high as a factor of 10 in the set studied. In the axial viewing mode the incandescent cup does not contribute to an increased background; however, the background and subsequent background noise levels are increased for most elements. Carrier gases were introduced into the cup via a hollow stem resulting in a reduction in the background signal, notably in the longer wavelength region. When 1000 ppm Freon-12 in argon is used as a carrier through the center of the cup, the normally problematic refractory elements are vaporized easily. Modifications and improvements to the design of the direct sample insertion device are also discussed.
68. Wayne Branagh, Ciara Whelan, Eric D. Salin, 1997,A System for Automatic Selection of Operating Conditions for ICP-AES, J. Anal. At. Spectrom, 12, 1307-1315.
[abstract]
The design of a system for automatic parameter and methodology selection for inductively coupled plasma atomic emission spectroscopy (ICP-AES) is presented. The ICP is an excellent excitation source that suffers less from matrix effects than other sources but is not altogether problem-free. To compensate, a variety of methodologies and approaches can be used to minimize matrix-induced error present in an analysis. For example, one can prepare matrix-matched standards, use standard additions or select instrumental parameters (rf power, pump rate and viewing height) specifically for the analytes of interest. Ideally, an Autonomous Instrument, operating without human intervention, needs to have the ability to determine the analytical parameters and methodology to apply to a sample. A measure of expected analytical error for a sample to be used by an Autonomous Instrument, the total interference level (TIL), is introduced. The TIL applies the results from a semiquantitative scan to a 'lookup' table to determine what the approximate expected error will be. It relies on a 'conservative' approach and assumes the effect of interferences on a particular analyte are not only linear, but additive. This approach was applied to samples with high concentrations of interferents and works well, providing acceptable estimates in 90% of analyte-interferent combinations (at 10% error tolerance). The emphasis of the discussion is placed on how well this system deals with 'problematic' samples, i.e. those samples where matrix effects cause considerable analytical error.
67. C. Sartoros, J-F Alary, J-M. Mermet, Eric D. Salin, 1997, Expert System Program for ICP-AES System Diagnosis. Spectrochim. Acta. Electronica, 52B, p 1923-1927.
[abstract]
This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hardcopy text is accompanied by two diskettes containing the installation program for the application. The main article discusses the purpose of this work and the Appendix provides instructions on the use of the program. ICP-AES performance can be followed by monitoring a series of atomic lines. QUID Expert is a Windows based program which uses line intensities from a standard solution in conjunction with a series of rules to determine when an ICP-AES is degrading and where the probable fault lies. The software provides other features such as a logbook and automatic recording to allow users to monitor system performance over extended times. In the tradition of modern expert systems, QUID Expert provides guidance as to what possible fault(s) might be present in the system and recommends remedial action(s).
66. C. Sartoros, Eric D. Salin, 1997, Pattern Recognition for Sample Classification using Elemental Composition - Application for ICP-AES. J. Anal. At. Spectrom. 12, 827-831.
[abstract]
Three pattern recognition techniques were investigated as tools for automatic recognition of samples: k-Nearest Neighbors, Bayesian Classification and the C4.5 inductive learning algorithm. Their abilities to classify 20 geological reference materials were compared. Each training and test example used 13 elemental concentrations. The data set was composed of 2582 examples obtained from CANMET in the form of results of analyses performed on these reference materials by different laboratories. It was found that all three pattern recognition techniques performed extremely well with a large data set of real samples. Bayesian Classification and k-Nearest Neighbors worked very well with small data sets.
65. Christine Sartoros, Eric D. Salin, 1997, A Comparison of Objective Functions for Optimization Techniques in Simultaneous Multi-Element Determinations in ICP Spectrometry , J. Anal. At. Spectrom, 12, 13-19.
[abstract]
Two objective functions for multi-element optimization in ICPAES were compared using signal-to-background ratios as a figure of merit. Complete three-dimensional response surfaces were generated for a number of elements (Ca, Cu, Al, Na, Ni, Mn and Ba) and two artificial 'elements' to evaluate the performance of both objective functions in locating the optimum compromise instrumental operating conditions in multi-element determinations. In the determination of the best compromise instrument operating conditions for most combinations of the elements used, both objective functions performed equally well; however, one occasionally performed significantly better than the other.
64. Wayne Branagh, Eric D. Salin, 1995, Reshaping the Monolith. The Autonomous Instrument Project, Spectroscopy (Eugene), 10, 20-4. Invited.
[abstract]
Progress is reported on the title project, involving the application of artificial intelligence to work with an inductively coupled plasma at. emission spectrometer (of a sequential scanning type). The authors have been developing software modules (e.g. system diagnosis, pattern recognition, optimization, methodol. selection).
63. J.M. Ren, R. Rattray, E.D. Salin, D. Conrad Grégoire, 1995, Assessment of Direct Solid Sample Analysis by Graphite Pellet Electrothermal Vaporization ICP Mass Spectrometry, J.Anal.At.Spectrom, 10, 1027-9.
[abstract]
Graphite pellet vaporization was evaluated as a method for solid sample introduction for ICP-MS. A detection limit of 0.1 ppb of Cd was obtained indicating that the technique might be very useful for screening. The accuracy was poor using the technique of external stds. and four ref. materials, suggesting that the technique of std. addns. might be required if the technique was to be used for anything other than semi-quant. measurements.
62. J-F. Alary, Genaro Hernandez, Eric D. Salin, 1995, Zeolite Slurry Analysis using Freon Assisted Graphite Furnace Vaporization for Inductively Coupled Plasma Atomic Emission Spectrometry Appl. Spectrosc. 49, 1796-1803.
[abstract]
Halogen-assisted electrothermal vaporization (ETV) was used as a sample introduction mechanism for inductively coupled plasma at. emission spectrometry. Freon-12Ò was used as a gas-phase halogenation reagent in the ETV graphite furnace to enhance vaporization of carbide-forming elements by converting them into metal halides. With Freon ETV, detection levels for Zn, Pb, Cd, Mn, V, Cu, Ti, and Ca were lower than those obtained with conventional nebulization of liq. stds. A zeolite sample was analyzed for the refractory elements chromium and vanadium. Without Freon, the signals for these elements were very low; however, with Freon, the signals were dramatically improved. Detection limits of 1.4 mg/g and 0.3 mg/g, resp., were obtained for these elements. A sheathing and cooling gas flow was introduced to reduce analyte vapor condensation on tubing walls and to promote aggregate formation. This addnl. flow enhanced the quality of signal with the zeolite but proved to be detrimental for the detn. of refractory elements in liq. stds. with or without halogenation. The precision of detn. for the zeolite sample varied from 3% for cadmium, to 6% for lead.
61. R. Rattray, Eric D. Salin, 1995, Chelation Preconcentration with Resin Analysis by Direct Sample Insertion Inductively Coupled Plasma Spectrometry, J.Anal.At.Spectrom, 10, 1053-58.
[abstract]
Batch preconcn. with Chelex-100 followed by direct anal. of the analyte-laden resin by direct sample insertion inductively coupled plasma at. emission spectrometry (DSI-ICP-AES) is described. The performance of the technique is element specific. Quant. retention of Cu, Zn, Cd and Pb on the resin is achieved, but only for Cu and Zn does the ratio of the signal before and after preconcn. approach the theor. preconcn. factor. This observation is mainly caused by the adverse effect of the remnants of the resin after ashing on the excitation properties of the plasma. This is clearly shown by monitoring the ratio of the intensity of a Pb ionic line to a Pb at. emission line. If the ashing temp. is increased, Cd and Pb are prematurely vaporized in the ashing stage, which was performed with inductive heating in the graphite DSI probe. Increasing the radiofrequency power sustaining the ICP improves the performance of the technique.
60. R.Rattray, Eric D. Salin , 1995, Aerosol Deposition Direct Sample Insertion for Ultra-Trace Elemental Analysis by Inductively Coupled Plasma Mass Spectrometry, J.Anal.At.Spectrom., 10, 829-36.
[abstract]
Direct deposition of a liq. sample as an aerosol into an inductively heated graphite direct sample insertion probe is described as a means of preconcn. and high efficiency sample introduction for ICP-MS. A two minute deposition at 0.25 mL min-1 resulted in 3s detection limits ranging from 0.06 to 1.8 pg mL-1 (0.03-0.9 pg) for the elements studied. These limits represent an element specific improvement averaging two orders of magnitude over the nebulizer/spray chamber-based sample introduction detection limits on the same instrument. The effect of varying several parameters related to the ICP and the deposition process was studied. The performance of the system with samples in an ethanol matrix was also demonstrated. The deposition and insertion procedure was automated, providing RSDs of .apprx.5% at the 1 ng mL-1 level. Anal. accuracy was assessed by replicate measurements of a Riverine Water Ref. Material for Trace Metals (SLRS-2, National Research Council of Canada). Good agreement between calcd. and certified values was obtained.
59. Miguel Catasus, Wayne Branagh, Eric D. Salin, 1995, Improved Calibration for Inductively Coupled Plasma Atomic-Emission Spectrometry using Generalized Regression Neural Networks, Appl. Spectrosc. 49, 798-807.
[abstract]
Artificial neural networks were recently used in different fields of science in applications ranging from pattern recognition to semi-quant. anal. Two types of neural networks were applied to the problems of spectral interferences, matrix effects, and the measurement drift in ICP-AES. Their performance was compared to that of the more conventional technique of multiple linear regressions (MLR). The two types of neural networks examd. were traditional multilayer perception neural networks and generalized regression neural networks (GRNNs). The GRNN is comparable to, or better than, MLR for modeling spectral interferences and matrix effects covering several orders of magnitude. In the case of an Fe spectral interference on Zn, the GRNN reduced the error from 81% to 24%, while MLR reduced the av. error to only 49%. For matrix effects caused by large backgrounds of Mg (0-10,000 ppm) on Zn, av. error was reduced to 55% from 67%. In the case of combinations of spectral overlaps and matrix effects, the GRNN reduced av. error by .apprx.10%. MLR performed poorly on systems involving matrix effects. GRNN is also a very promising tool for the correction of drift caused by fluctuations in power levels, reducing drift over a two-hour period from 2.3% to 0.6%. GRNNs, both by themselves and in multinetwork combinations, seem to be highly promising for the correction of nonlinear matrix effects and long-term signal drift in ICP-AES.
58. Guy Légère, Eric D. Salin, 1995, Capsule Based Microwave Digestion, Appl. Spectrosc., 49, 14A-22A.
[abstract]
A review, with 6 refs., is given on sample digestion in capsules using microwaves.
57. Wayne Branagh, Huinan Yu, Eric D. Salin, 1995, A Comparison of Pattern Recognition Techniques for Sample Classification using Elemental Composition - Applications for ICP-AES. Appl. Spectrosc. 49, 964-970.
[abstract]
Pattern recognition is very important for many aspects of data anal. and robotic control. Three pattern recognition techniques were examd.-k-Nearest Neighbors, Bayesian anal., and the C4.5 inductive learning algorithm. Their abilities to classify 71 different ref. materials were compared. Each training and test example consisted of 79 different elemental concns. Different data sets were generated with relative std. deviations of 1, 3, 5, 10, 30, 100, and 500%. Each data set consisted of 2000 examples. These sets were used in both the training stages and in the test stages. C4.5's inductive learning algorithm had a higher classification accuracy than either Bayesian or k-Nearest Neighbors techniques, esp. when large amts. of noise were present in the systems.
56. J-F. Alary, Eric D. Salin, 1995, Rapid Sample Preconcentration for Spray Deposition for Electrothermal Vaporization Inductively Coupled Plasma Spectrometry Spectrochim. Acta. 50B, 405-413, (Invited).
[abstract]
The deposition of aq. sample in an electrothermal vaporization unit (ETV) is implemented by spraying onto a graphite tube heated at 160°. The H2O is evapd. continuously and vented by a flow of Ar, leaving and analytes to the inner walls of the graphite cuvet. The analytes are later atomized at high temp. and direct to an inductively coupled plasma for at. emission spectrometry (ICP-AES). The effects of observation height, Ar flow in the furnace unit at atomization, and plasma energy on the signal-to-noise ratio were studied. The combination of the advantages of ETV with a sample vol. of 1 mL provides detection limits for Cd (0.06 ng/mL), Pb (0.3 ng/mL), Zn (0.02 ng/mL) and Cu (0.04 ng/mL) which are an improvement of two orders of magnitude when compared with conventional nebulization. Also, the ETV allows a more interface to the plasma than similar direct sample insertion (DSI) expts.
55. C. Skinner, E.D. Salin, 1995, Determination of Lead in Soils Surrounding a Lead-Acid Battery Manufacturer, Water Pollution Research Journal of Canada, 20, 299-304.
[abstract]
Soil lead levels were determined on and around a former battery manufacturing site. Lead concentrations ranging from 120 ppm to 5.1% were found. The highest concentrations were found close to the factory site. When it was possible to obtain samples over a continuous depth range, it was found that lead concentration decreased with depth and that it increased above underground foundations.
54. J.M. Ren, Eric D. Salin, 1994, Direct Solid Sample Analysis Using Furnace Vaporization with Freon Modification and Inductively Coupled Plasma Atomic Emission Spectrometry. Part I. Vaporization of Oxides and Carbides. Spectrochim. Acta., 555-566.
[abstract]
A modified electrothermal vaporization (ETV) furnace was used as a high temperature reaction chamber and a vaporizer for direct solid sample analysis with inductively coupled plasma atomic emission spectrometry (ICP-AES). At temperatures ranging from 1000 to 2400°C, pure oxides and carbides were converted to lower boiling point halides and evaporated. The samples were deposited as 10 µl of 1% slurries of the powdered samples in distilled water. Experimental results showed that, with the use of Freon-12 as a gas phase halogenation reagent, near 100% vaporization was achieved for the powdered samples studied, Al2O3 (b.p. 2980°C, <10 µm), SiO2 (b.p. 2230°C, <44 µm), ZrO2 (b.p. 5000°C, <74 µm) and TaC (b.p. 5500°C, typically 5 µm). The same was true for WC (b.p. 6000°C, <10 µm) if BaCl2 was used as a second halogenation reagent. The approach appears to have the potential to vaporize a wide variety of samples with inorganic matrices. Probably the importance of our work does not lie in the fact that we vaporized tungsten carbide. Rather, it lies in the fact that tungsten carbide is one of the most refractory compounds known to man.
53. J.M. Ren, Eric D. Salin, 1994, Direct Solid Sample Analysis Using Furnace Vaporization with Freon Modification and Inductively Coupled Plasma Atomic Emission Spectrometry. Part II. Analysis of Real Samples, Spectrochim. Acta., 567-575.
[abstract]
The first part of our work [J. M. Ren and E. D. Salin, Spectrochim. Acta 49B, 555-566 (1994)] showed that pure oxides and carbides were vaporized nearly completely with the use of an electrothermal vaporization (ETV) furnace as a high temperature reaction chamber and Freon-12 as a gas phase halogenation reagent. This paper presents the results of direct analysis of four marine sediment reference materials and one coal fly ash reference material. The samples were loaded into the electrothermal vaporization (ETV) furnace in 10 µl of 1% slurries in distilled water. Among the eight elements monitored, good or reasonable linearity was observed between the background corrected peak area and the reference concentration (in the solid phase) for three trace elements: Cu (18-452 ppm), Mn (179-513 ppm) and Zn (119-824 ppm); and two major elements: Al (6.25-14.3%) and Fe (3.05-9.4%). The relative standard deviation (RSD) of the analysis varied from 3 to 15%. Compared to routine solid sample digestion procedures, the present approach was extremely easy and fast and appears to offer considerable promise.
52. Guy Légère, Eric D. Salin, 1994, Fast Clearing Spray Chamber for ICP-AES. Appl. Spectrosc., 48, 761-765.
[abstract]
The rapid-clearing spray chamber design utilizes two crit. features for a rapid-clearing system - a nebulizer wash and a high-vol. gas flush. The combination of these two features with supporting design features provides a system which can clear out a signal of Fe or Zn from 500 ppm to undetectable levels (below 10 ppb) in about 20 s. A tubular injector is used in the ICP torch to minimize plasma disturbance during the gas flush cycle. Several modifications to the spray chamber were necessary to handle the nebulizer wash efficiently.
51. D.P. Webb, J. Hamier, E.D. Salin, 1994, The Autonomous Instrument, A Design. Trends. Anal. Chem., 13, 44-52 (invited).
[abstract]
A design of software for an autonomous atomic emission instrument is presented with the emphasis on a subsystem for automatic selection of calibration methodology for inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The suitability of the 1st-Class expert system shell for development and final implementation of this system is discussed. The calibration methodology system is described in the context of ongoing research into the development of autonomous ICP instrumentation.
50. J.M. Ren, J. Guy Légère, Eric D. Salin, 1993, Experiment Alignment by Reverse Path Laser Imaging, Technical Note Appl. Spectrosc., 11, 1953-1954.
[abstract]
In many research laboratories, modular spectrometric components are used. If experiments are often changed, alignment can be time consuming and difficult. In our atomic emission spectrometry (AES) laboratory, the light source and the spectrometer are not physically connected together, and the spectrometer is mobile—which necessitates frequent checking of the focusing and the alignment of the system. Previously we used a lens to collect light from our inductively coupled plasma for AES experiments. The focusing and alignment had been done by observing the plasma image on the entrance slit. While this approach is visually appealing, chromatic aberrations will inevitably cause defocusing in the ultraviolet region of the spectrum, and it is critical that we be able to image properly in this region. Recently we switched to the use of an off-axis concave mirror to eliminate chromatic aberrations caused by the use of the lens. It became evident during the design phase of this conversion that alignment would become more challenging due to the off-axis arrangement required by this configuration (Fig. 1).
49. Robin Rattray, Jorge Minoso, Eric D. Salin, 1993, Rapid Sample Preconcentration by Aerosol Deposition for the Determination of Trace Elements by Inductively Coupled Plasma Spectrometry, J. Anal. At. Spectrom, 8, 1033-1036.
[abstract]
A new approach to sample preconcn. for inductively coupled plasma spectrometry has been developed. The method involves deposition of the sample soln. as an aerosol into an inductively heated, graphite, direct sample insertion probe. With a deposition time of 2 min and a sample vol. of 0.5 mL, detection limits for Cu, Zn, Cd and Pb were 0.05, 0.12, 0.10, and 0.07 ppb, resp. These limits represent an improvement of almost three orders of magnitude over those obtained by conventional sample introduction in the same system. The relative std. deviation was <5% at the 10 ppb level. The conditions used and some performance characteristics are presented and discussed.
48. J.M. Ren, Eric D. Salin, 1993, Evaluation of a Modified Electrothermal Vaporization Sample Introduction System for the Analysis of Liquids by Inductively Coupled Plasma Atomic Emission Spectrometry, J. Anal. At. Spectrom., 8, 59-63.
[abstract]
A Perkin-Elmer electrothermal vaporization (ETV) furnace was modified for use as a sample introduction device for inductively coupled plasma at. emission spectrometry (ICP-AES). The major modification made is the addn. of sheath and cooling gas flows. The sheath gas provides a thin sheath layer between the analyte vapor and the wall of the transport tube to prevent vapor condensation, and the cooling gas cools the analyte vapor to promote aggregation formation. Expts. with liq. samples showed that addn. of these gas flows increases the analyte transport efficiency and reduced matrix effects on the transport efficiency. The results also suggest that the carrier gas flow rate affects the peak shape and peak intensity of the copper signal, probably by changing the vaporization rate. With 10 mL sample soln. loadings, the detection limits range from 1 to 6 ppb for Cd, Pb, Zn, Mn and Cu, and the precision (relative std. deviation) varies from 3 to 6%. The system is flexible and holds promises for direct solid sample anal.
47. D.P. Webb, E.D. Salin, 1992, An Electronic Aid for Line Selection for Scanning Inductively Coupled Plasma Atomic Emission Spectrometers., Spectrochim. Acta, 47B, pp E1487-E1594.
[abstract]
This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). Accompanying this hard copy text is a disk containing the program, source files, data files and a brief manual along with a few programming notes. The main article discusses the purpose of this work, and the Appendix provides brief instruction on the use of the program, manipulation of the data, and source code. An automatic file selection system for the control of a rapid scanning spectrometer performing atomic emission spectrometry has been developed using the PROLOG language. The system can be 'taught' the elemental composition of a given sample type. It uses this information (when available) to generate a linear search strategy which minimizes the number of lines that need to be measured. The rules used by the system can be observed during system operation to allow a trace of the logic. Reading of the initial data base takes no more than 6 s and then decisions are made in less than 1 s per line.
46. D.P. Webb, E.D. Salin, 1991, The Autonomous Instrument: Concept to Prototype, Intelligent Instruments and Computers. 5, 185-193 (invited).
[abstract]
Abstract not available.
45. V. Karanassios, L. Usypchuck, P. Moss, Eric D. Salin, 1992, A Flame Sample Introduction System for ICP-AES. J. Anal. At. Spectrom. 7, 1243-1247.
[abstract]
An oxygen-hydrogen flame sample introduction system for inductively coupled plasma (ICP) at. emission spectrometry is discussed. A total consumption burner oxyhydrogen flame-ICP tandem source was used for the anal. of slurries of marine sediment Certified Ref. Materials with particle diams. of less than 2 mm. Significant memory effects were obsd. Detection limits were 0.3 ppm for Cu, 1 ppm for Mn and 1 ppm for Zn and the precision ranged between 1% and 3% (both detd. using aq. stds.).
44. L. Blain, E.D. Salin, 1992, Application of AgCl as a Thermochemical Additive for the Determination of Refractory Elements in Sediment Samples by Direct Sample Insertion Inductively Coupled Plasma Atomic Emission Spectrometry, Spectrochim.Acta. 47B, 1471-1481.
[abstract]
Trace levels of refractory elements have been determined in a solid sediment reference material (PACS-1) by direct insertion into an inductively coupled plasma (DSI-ICP-AES), using AgCl as a volatilization enhancing thermochemical additive. The method of standard additions was used for calibration. It was found that powdered metal oxide standards (SPEX g-standards) were adequate spiking standards for Co, Cr, Ni and V in PACS-1. The reproducibility of the measurements was between 10 and 25% RSD. The accuracy of the determinations is fair below 50 µg g-1, with typical errors falling below 10%, but it degrades at the higher concentrations to errors of approximately 20%.
43. D. P. Webb, J. F. Power, E.D. Salin, 1992, ICP Sample Matrix Identification by Acoustic Signal, Appl.Spectrosc., 46 (9) 1362-1367.
[abstract]
A novel technique for rapidly detg. properties of the sample matrix of nebulized samples in inductively coupled plasma spectrometry via acoustic signature is discussed. Properties such as surface tension and high dissolved salts can be detd. by analyzing the acoustic signal produced by the sample nebulization process. With digital signal processing equipment, detn. of the presence of org. matrixes or high-salt matrixes should be possible before the plasma or the nebulizer is adversely affected.
42. L. Blain, E.D. Salin, 1992, Observations on the use of Pellet Direct Sample Insertion for Inductively Coupled Plasma Atomic Emission Spectrometry, Spectrochim.Acta, 47B, 388-423.
[abstract]
The feasibility of analyzing geological materials by the use of the direct sample insertion (DSI) technique into the inductively coupled plasma was assessed with a sediment reference material, PACS-1 (NRCC). Sharp and intense peaks were recorded for elements of high and intermediate volatility (As, Cd, Cu, Hg, Mn, Pb, Se, Sn, Zn) after the insertion of pellets prepared from 1:5 mixtures of PACS-1 in graphite. Probe geometry and plasma RF power were optimized to enchance both the magnitude of the signals and the temporal resolution of spectral overlaps. A variable integration time base was found essential to allow good observation of the signals of analytes ranging from volatile trace level elements to refractory matrix constituents. The use of thermochemical additives to enhance the vaporization of refractory elements was investigated. It was found that chloride releasing reagents were preferable to fluoride salts, because the fluorides caused a sudden massive release of Si into the plasma, which resulted in severe physical and spectral interferences.
41. L. Blain, E.D. Salin, 1992, Methodological Solutions for the Analysis of Sediment Samples by Direct Sample Insertion Inductively Coupled Plasma Atomic Emission, Spectrochim.Acta., 47B, 205-217.
[abstract]
Result for the calibration of the direct sample insertion technique (DSI) with sediment standards are reported for inductively coupled plasma atomic emission spectrometry (ICP-AES). It has been found that internal standardization can compensate for variations in volatilization interferences and changes in excitation conditions between sediment standards, for elements of high and intermediate volatility (Cd, Cu, Hg, Mn, Pb and Zn). It has also been found that the method of standard additions allows accurate calibration of the technique. Sub-ppm detection limits were typical for elements of high and intermediate volatility.
40. E.D. Salin, P.H. Winston, 1992, Machine Learning and Artificial Intelligence: An Introduction, Anal.Chem., 64(1) 49A-60A.
[abstract]
Abstract not available.
39. P. Moss, E. D. Salin, 1991 Flow Injection Preconcentration Coupled with Direct Sample Insertion for Inductively Coupled Plasma Atomic Emission Spectrometry, Appl. Spectrosc., 45, 1581-1586.
[abstract]
A flow injection (FI) preconcn. system has been coupled with a direct sample insertion (DSI) system for inductively coupled plasma at. emission spectrometry (ICP-AES). The FI system provides a preconcn. factor of approx. 30. The DSI detection limit improvement, as compared to conventional nebulization detection limits, is element specific and ranges between 10 and 130 when a cup specifically designed for liq. work is used. The FI-DSI hybrid provides detection limit improvements ranging between 140 and 1200 for the elements tested-Cu, Pb, and Zn. Precision of the FI-DSI-ICP system avs. 4% RSD for these three elements. FI processing time is 6.0 min with the use of 5-mL injection vols. The system offers considerable potential for further improvement by increasing the injection vol. and improving the interface to the DSI.
38. V. Karanassios, F.H. Li, B. Liu, E.D. Salin, 1991, A Rapid Stopped Flow Microwave Digestion System. J. Anal. At. Spectrom., 6(6), 457-63.
[abstract]
A prototype system for stopped-flow microwave-assisted wet digestions has been developed. A coiled Teflon perfluoroalkoxy tube serves both as a sample container and as a digestion vessel. A sample plug, consisting of a water slurry mixed with an acid mixt., is pumped into the coil. Sample flow is stopped, the coiled tube is sealed (by closing an input and an output valve), and microwave power is applied for 2 min for digestion of the sample. Methodol. was developed using powd. botanical ref. samples and was tested with powd. botanical and biol. ref. materials. The digests were analyzed by inductively coupled plasma at. emission spectrometry. In addn. to comparisons with certified values, the results were compared with those obtained by conventional open-vessel hot-plate digestions, by open-vessel microwave digestions, and by digestions taking 32 min by using the coiled tube system. Precise, and in many instances, quant. digestions were obtained using a net digestion time of 2 min. Elemental recoveries were sample type and digestion time dependent and were comparable with, and sometimes, superior to those obtained when using a 3-h long hot-plate digestion. In this preliminary study, characteristics, limitations, and future directions are discussed.
37. V. Karanassios, J.M. Ren, E.D. Salin, 1991, An Electrothermal Vaporization Sample Introduction System for the Analysis of Pelletized Solids by Inductively Coupled Plasma Atomic Emission Spectrometry, J. Anal. At. Spectrom., 6(7), 527-33.
[abstract]
A new approach for solid sample introduction into a furnace for use with an inductively coupled plasma has been developed and tested with at. emission spectrometry. A powd. sample is mixed with graphite and pressed into a pellet. The pellet is placed between the electrodes of a modified electrothermal vaporization device. A current causes rapid ohmic heating of the pellet and results in analyte vaporization. The vapor is swept into the plasma by an Ar carrier gas stream. In this preliminary report, system characterization with single element oxide stds. and testing with powd. botanical samples are described. The system shows considerable promise for rapid screening of botanical samples of environmental concern. Detection limits for Cd, Zn and Pb of 1,3 and 0.6 ppb (300, 800 and 150 pg) were obtained using the oxide stds.).
36. L. S. Gervais, E.D. Salin, 1991, Heated Sample Introduction System for the Analysis of Slurries by Inductively Coupled Plasma Atomic Emission Spectrometry, J. Anal. At. Spectrom., 6(1), 41-7.
[abstract]
A slurry sample introduction system with a heated spray chamber followed by a condenser has been evaluated. Signal intensities (calibration curve slopes) increased for liquid standards by a factor of 11 while for solid (slurry) samples, intensities increased by a factor of approximately 3. Despite these intensity increases, detection limit improvements were marginal due to a comparable increase in noise. Experimentation demonstrated that it was necessary to use a continuous tubular injector tube to reduce fluctuations in the plasma. Injector-gas composition appeared to have a major effect on the particle decomposition capability of the plasma.
35. L. S. Gervais, E.D. Salin, 1991, Inserted Injector Tubes for Inductively Coupled Plasma Spectrometry, J. Anal. At. Spectrom., 6(6), 493-5.
[abstract]
Expts. are described in which an inductively coupled plasma is operated with an injector tube that is inserted into the body of the plasma. The system is highly tolerant to pressure fluctuations form the sample introduction system. Both wide (6 mm o.d., 3 mm i.d.) and narrow (2 mm o.d., 1 mm i.d.) injector tubes were studied. Interestingly, the intensities obsd. with the two different injector tubes were fairly similar. Alumina was found to be a superior material since graphite appeared to reduce the power of the plasma.
34. D.P. Webb, E.D. Salin, 1990, Selection of Spectral Windows for Plasma Atomic Emission Spectrometry, Talanta, 37(1), 33-8.
[abstract]
A program was developed to evaluate the no. of spectral windows required to perform elemental anal. by inductively coupled plasma-at. emission spectrometry, given a certain spectral window width. The data indicate that photodiode array systems (sequential slew scan) with as few as 7 or 8 acquisitions (windows) might be viable. With smaller windows, approaching in size those used by direct-reading spectrometers, it appears that conventionally designed spectrometers with photomultiplier tube detectors could use between 29 and 37 windows to det. 59 elements. This indicates that a general purpose direct-reading spectrometer may be feasible.
33. L. Blain, E.D. Salin, M. Powell, D.W. Boomer, 1989, Probe Design for the Direct Insertion of Solid Samples in the Inductively Coupled Plasma for Analysis by Atomic Emission and Mass Spectrometry, J. Anal. At. Spectrom, 4(8), 721-5.
[abstract]
An alternative to the conventional probes used for the direct introduction of solid samples into the inductively coupled plasma is presented. Powd. samples were mixed with graphite and pressed into pellets, which were then inserted into the plasma. Unlike other probes, such as graphite cups, the whole body of these pellets was composed of sample mixt., so more sample could be inserted into the plasma at once. For some elements, the resulting improvement in detection limits was commensurate with the increased mass of sample whereas for other elements it was greater, suggesting that the absence of walls on the probes may result in better heat and mass transfers.
32. D.P. Webb, E.D. Salin, 1989, A Line Selection Expert System for the Control of Scanning Spectrometers Performing Inductively Coupled Plasma Atomic Emission Spectrometry, J. Anal. At. Spectrom, 4(8), 793-6.
[abstract]
An expert system for control of a rapid scanning spectrometer to perform at. emission spectrometry was developed using the Prolog language. The expert system can be taught the elemental compn. of a given sample type. It uses this information (when available) to generate a line-search strategy which minimizes the no. of lines that need to be measured. The rules used by the system can be obsd. during system operation to allow a trace of the logic. Reading of the initial database takes no more than 6 s and then decisions are made in < 1 s per line.
31. R. L. A. Sing, E. D. Salin, 1989, Introduction of Liquid Samples into the Inductively Coupled Plasma by Direct Insertion on a Wire Loop., Anal. Chem., 61(2), 163-9.
[abstract]
The use of a wire loop as sample support for direct insertion of samples into the inductively coupled plasma results in very rapid volatilization of the sample, yielding high momentary concns. of the analyte in the viewing zone. The shapes of the resulting transient signals for a no. of elements (Ag, Cd, Cr, Mg, Pb, V, and Zn) are presented. Tungsten wire is used for the majority of the study but contributes spectral overlaps that cannot be temporally resolved from the analyte peak in some cases. Tantalum provides better temporal resoln. but suffers from a short lifetime. Detection limits for the elements studied are in picogram to subpicogram range. It is demonstrated that the Cu concn. detection limits can be improved a factor of at least 10 by multidrop insertions. Matrix effects were investigated with Ca as matrix element. Increasing the concomitant Ca concn. affects the peak shape significantly. The peak heights vary considerably but peak area remains const. for 100 mg/L Cu in the presence of 0 to 104 mg/L Ca. For Cd a slight decrease in peak area occurs above 103 mg/L Ca.
30. J. Power, E. D. Salin. 1988, Performance of a mode mismatched thermal laser lens photodiode array spectrometer with Fourier transform analysis of beam profiles, Anal. Chem., 60(9) 838-842.
[abstract]
A thermal lensing system using photodiode array detection is described for low-level molecular absorbance measurements. The beam profile is converted for use in the frequency (Fourier) domain rather than the spatial domain since this format seems to provide superior presentation. The effects of laser power and other design considerations are discussed.
29. T. W. Williams, E. D. Salin, 1988, Hazards of a naive approach to detection limits with transient signals, Anal. Chem., 60(7) 725-727.
[abstract]
Exptl. data were simulated to evaluate the validity of commonly used criteria for the evaluation of detection limits for transient signals in anal. methods. Both raw noise and filtered noise data sets demonstrate emphatically that 99.9% confidence limits are invalid using several different computational approachs. The degree of deviation depends on the width of the time windows in which one searches for the peak and on the computation method used to det. that std. deviation of the signal.
28. C. J. Monasterios, E. D. Salin, 1986, Determination of Cu and Zn in human head hair by inductively coupled plasma atomic emission spectrometry with a direct sample insertion device, Anal. Chem, 58(4)780-5.
[abstract]
The anal. of single strands of hair without digestion is demonstrated using a direct sample insertion device and inductively coupled plasma at. emission spectrometry. Cu and Zn are detd. in 3 donors and the results compare well with thoe of conventional methods. The detection limits for various elements in a 1-mg hair sample ranged 0.2-10 ppm in the solid form.
27. D. W. Boomer, M. Powell, R. L. A. Sing, E. D. Salin, 1986, Application of a wire loop direct sample insertion device for inductively coupled plasma mass spectrometry, Anal. Chem., 58(4) 975-6.
[abstract]
A W wire loop direct sample insertion device is used to deliver desolvated 10 mL samples directly into the center of an inductively coupled plasma where vaporization and ionization take place prior to mass spectrometry detection. Detection limits are 1 order of magnitude lower than obtained using conventional nebulization.
26. S. W. McGeorge, E. D. Salin, 1986, Spatial resolution enhancement for linear photodiode array atomic spectrometry, Spectrochim. Acta, 41B(4) 327-33.
[abstract]
The theory and exptl. data are presented for a spatial resoln. enhancement technique for use with a linear self-scanning photodiode array. The technique uses the photodiode geometry and the intensity profile of the image to det. image positions to subdiode accuracy. The theory can be used to deduce an unknown image profile by translating the image across 2 photodiodes.
25. D. L. Luffer, E. D. Salin, 1986, A rapid throughput nebulizer-spray chamber for inductively coupled plasma atomic emission spectroscopy, Anal. Chem., 58(3) 654-6.
[abstract]
A spray chamber of small dimensions was evaluated with respect to clearing time and short term and long term signal-to-noise ratio behavior. Results are compared with those found for a conventional configuration with the same Meinhard nebulizer. The small spray chamber exhibited clearing times a factor of 2.5 shorter, and both short term and long term signal-to-noise ratios are significantly better.
24. E. J. Zuck, E. D. Salin, 1985, Evaluation of a low cost imaging system for analytical applications, Anal. Chem., 57(12) 2413-2414.
[abstract]
A low cost image sensor is used to read the meniscus on a buret. The reading accuracy and precision is comparable to that of a human user. Illumination methods and levels are important, but adjustment was greatly simplified by observing the progress of the adjustment directly on a computer video monitor. The limitations of the field of vision are discussed.
23. S. W. McGeorge, E. D. Salin, 1985, Enhancement of wavelength prediction accuracy using a linear photodiode array as a detector for inductively coupled plasma atomic emission spectrometry, Anal. Chem, 57(13) 2740-2743.
[abstract]
An empirical technique which furnishes an enhanced wavelength measurement accuracy for linear photodiode array (PDA) detection systems is described. The technique is based on a math. interpolation and produces subdiode spatial resoln. A series of known lines is used to calibrate the detection system and the resulting information is then used to compensate for the nonlinear change in dispersion across the spectral region falling on the PDA. A single known line can be used to allow the measurement of the wavelength of unknown lines within a given spectral window to a precision of better than 0.01 nm.
22. S. W. McGeorge, E. D. Salin, 1985, The effect of integration time and interval on precision with three pneumatic nebulizers used for inductively coupled plasma atomic emission spectrometry, Appl. Spectrosc., 39(6), 989-93.
[abstract]
The long-term behavior of three popular pneumatic nebulizers was observed and compared, with particular attention given to signal-to-noise ratio. Results indicate that sample changeover time and, consequently, spray-chamber clearing time, should be as short as possible. Precision varied widely for each nebulizer depending on the interval between data values. Integration times as short as 0. 1 s can yield relative standard deviations of about 1%. Each of the nebulizers was capable of delivering better than 1% RDS, and two provided RSDs less than 0. 4% under certain conditions. The implications of these measurements on instrument and experiment design are discussed.
21. Magdi M. Habib, Eric D. Salin, 1985, Controlled potential electrolysis coupled with a direct sample insertion device for multielement determination of heavy metals by inductively coupled plasma atomic emission spectrometry, Anal. Chem., 57(11) 2055-9.
[abstract]
The application of controlled potential electrolysis with both graphite electrodes and a hanging mercury drop electrode as a separation and preconcentration technique for inductively coupled plasma (ICP) atomic emission spectrometry using the direct sample insertion device (DSID) is described. Heavy metal ions in aqueous solution are determined. With a deposition time of 5 min the detection limits under compromise conditions are 2. 4, 680, 2. 0, 175, 25, and 259 ng/mL for Cu, Pb, Zn, Cd, Ni, and Co, respectively. A determination of Cu at the 63 ng/mL level in artificial seawater (3. 5% salinity) was made with a 4% error.
20. S. W. McGeorge, E. D. Salin, 1985, Data acquisition considerations for spectrometry with photodiode array detection systems, Spectrochim. Acta, 40B(8) 1039-1045.
[abstract]
A consideration of data acquisition for spectrometry with photodiode array detection systems shows that care must be taken when designing the software and hardware for a data acquisition system for any detection system. It is esp. important in the case of the linear photodiode array and similar devices which provide a significant amt. of detector noise. It is also important that the choice or operation of data acquisition hardware and software be integrally linked to the expt. itself. This linkage must include a knowledge of the range of magnitude of the exptl. signals as well as the noise of these signals. The calcns. are simple and well suited to real time acquisition for use in expts. which produce transient signals. The use of the dynamic range figure of merit commonly provided by instrument and component manufacturers can be highly deceptive when used loosley. The usable ranges, both dynamic and max., are terms which more correctly describe the range of exptl. signals which can be obsd. with a given detection system.
19. S. W. McGeorge, E. D. Salin, 1985, Signal-to-noise considerations for rapid scan atomic spectrometry with an inductively coupled plasma, Spectrochim. Acta, 40B(3) 447-59.
[abstract]
The blank photon flux from an inductively coupled plasma was measured with a conventional 1-m spectrometer for the spectral region from 200 to 450 nm. This flux was then used to calc. the min. integration time required before quantum noise (shot noise from the photon flux) becomes significant under various conditions. The calcns. demonstrate that blank integration times may be much shorter than the times spent integrating either samples or stds. without degrdn. of the total measurement. Comparison to extrapolated values for a high resoln. spectrometer configuration indicate that min. integration times requirements will vary drastically with wavelength, slit width, and spectrometer configuration. The data demonstrate that integration times may be as short as 1 ms under certain circumstances indicating that very rapid scan data acquisition is feasible for inductively coupled plasma-at. emission spectrometry if done with intelligent interactive control.
18. S. W. McGeorge, E. D. Salin, 1985, Some theoretical and practical considerations to the application of linear photodiode arrays for inductively coupled plasma emission spectrometry, Spectrochim. Acta, 40B(3) 435-45.
[abstract]
Expressions were developed and used to predict the performance of a linear photodiode array when used with a conventional dispersive spectrometer for inductively coupled plasma (ICP)-at. emission spectrometry in 200-450 nm region. The photon flux from the ICP and the relative std. deviation (RSD) at high concns. were used in the equations to calc. the degrdn. of performance to be expected at and above the detection limit for integration times up to 10 s. Significant degrdn. is predicted only <230 nm, and this degrdn. is less than a factor of 10 at 200 nm for an ICP with an RSD of 0.2%. One-second integration times are possible with noisier ICPs or at longer wavelengths without significant performance degrdn. by the photodiode array.
17. S. W. McGeorge, E. D. Salin, 1984, Image sensor applications in analytical atomic spectroscopy, Prog. Anal. At. Spectrosc., 7 387-410.
[abstract]
A review with 113 refs. Imaging detectors for extg. anal. useful information from the spectra in at. spectroscopic anal. are discussed.
16. E. D. Salin, 1984, Performance characterization of an instrument, J. Chem. Ed., 61(1) 70-72.
[abstract]
There is a tendency among certain students to have nnquestioning faith in instrumentation. This is particularly true of modern instrumentation with digital readout. These students reDort data to a phenomenal number of sienificant figures while expecting a corresponding accuracy. An appreciation of the power of modern instrumentation must he tempered
with an awareness of its limitations. Students should apply to instrumentation the same statistical awareness that is so conveniently and commonly applied to classical techniques. Propagation of error techniques can he used to pinpoint
instrumental limitations and breakdowns as well as they can be nsed to demonstrate the capabilities and ultimate
limitations of volumetric and gravimetric methods. With this in mind, an experiment has been developed for use in our second analytical chemistry course. We have used an atomic emission apparatus as the experimental vehicle; however, the techniques are generally applicable.
15. Eric D. Salin, R. L. A. Sing, 1984, Microsample liquid analysis with a wire loop direct sample insertion technique in an inductively coupled plasma, Anal. Chem., 56(13) 2596-8.
[abstract]
The direct insertion of a sample-coated W wire into the inductively-coupled plasma for emission spectrometric detn. of trace levels of metallic species in aq. solns. was investigated. Detection limits of 0.2 and 0.08 ng/mL for Cu and Zn, corresponding to abs. detection limits of 2 ´ 10-12 and 0.8 ´ 10-12 g, were obtained by using 10-mL samples. The precision is 5% (relative std. deviation) and calibration curves are linear over 4 orders of magnitude. Temporal resoln. may minimize the effect of some spectral overlaps. Peak area provides a measurement of concn. which appears to be independent of total salt concn. at the 0.1% level for Ca.
14. R. L. A. Sing, Eric D. Salin, 1984, A versatile low-cost laboratory computer network, Talanta, 31(8) 565-71.
[abstract]
An inexpensive but powerful computer network particularly suited to the research lab. is discussed. The primary advantages of the system are low cost, flexibility, freedom of choice of manufacturer, and convenience of upgrading. The principal limitations are speed of data transfer and the requirement for a certain level of skill during setting up. The system operates with both the CP/M and MP/M operating systems, but the principles of operation are generally applicable.
13. Eric D. Salin, Magdi M. Habib, 1984, Electrochemical preconcentration and separation for elemental analysis by inductively coupled plasma emission spectrometry, Anal. Chem., 56(7) 1186-8.
[abstract]
The application of electrochem. preconcn. for samples to be used for inductively-coupled plasma-at. emission spectrometry is discussed. Specific elements are deposited electrochem. on a Hg-coated graphite electrode. The electrode is then inserted into the inductively-coupled plasma. Detection limits for Cu are improved by 2 orders of magnitude over those obtained with conventional nebulization. The precision of the technique is 3%, well above the detection limit.
12. R.L.A. Sing, S. W. McGeorge.; E.D. Salin,., 1983, Laboratory data-acquisition capabilities of microcomputer high-level languages, Talanta, 30(10), 805-809.
[abstract]
A comparison is made of the efficiency and precision of various high-level languages in data-acquisition programs for microcomputers.
11. Scott W. McGeorge, Eric D. Salin, 1983, Control and dynamic range extension of linear photodiode arrays by a single board computer, Spectrochim. Acta, Part B, 38B(4), 633-8.
[abstract]
A complete interface for data acquisition and control of Reticon series arrays using an inexpensive microcomputer (Rockwell AIM-65) is described with sp. application to at. spectra (inductively coupled plasma). Data collection techniques are illustrated that provide a dynamic range extension for intense signals.
10. Eric D. Salin,. 1982, Computer Interfacing for Chemists, J. Chem. Ed., 59(1), 53-56.
[abstract]
Traditionally, computers have heen used hy chemists for computation purposes. This has included hoth the processing of experimental data and calculational modeling. Recent develooments in electronic technoloev have drastically reduced the Eost and size of computers with a subsequent rwolution in modern instrumentation and lahoratory data acquisition capabilities. Since the modern chemist is quite likely to encounter computer-controlled instrumentation and general purpose lahoratory computers, it is a university's responsihility to prepare a student for these encounters. The needs of a new graduate are somewhat difficult to predict because of the many career paths which may he followed upon graduation; however, students studying for advanced degrees are quite likely to spend much of their working lives involved either directlv with comvuters or suvervisine those who are.
9. Scott W. McGeorge,.; Eric D. Salin,. 1982, Detection systems for multielement analysis with inductively coupled plasma atomic emission spectroscopy, Can. J. Spectrosc., 27(2), 25-36.
[abstract]
A review with 38 refs.
8. J. D. Ingle,, Jr.; M. J. White, Eric D. Salin, 1982, Effect of noise and rate computational approach on the precision of rate measurements, Anal. Chem., 54(1), 56-8.
[abstract]
The effect of noise in the reaction monitor signal and of reaction condition irreproducibility on the precision of rate measurements is discussed. Noise limits the precision at and near the detection limit and a procedure is presented for evaluating the expected precision with any reaction monitoring system when noise is limiting. In this procedure, real noise data from absorbance and fluorescence spectrometers are digitized and added to a computer-generated slope. Least-squares, fixed-time, and variable-time rate computational approaches are used to extract rate information. The precision of rate measurements is found to be proportional to the ratio of the change in reaction monitor signal measured to the peak-to-peak noise and to be independent of the rate computational approach.
7. Eric D. Salin, M.W. Blades, Gary Horlick, 1982, Laboratory Data-Acquisition Capabilities of Microcomputers, Talanta, 28, 519-525.
[abstract]
Some microcomputers have been evaluated in terms of their features and capabilities for basic laboratory data-acquisition tasks. The systems studied include the SDK-80 (8080), SDK-85 (8085), and KIM-1 (6502) single-board microcomputers, and the PET consumer/hobby-market microcomputer. Data-acquisition software benchmarks were tested on all the systems, and inexpensive analogue-to-digital and digital-to-analogue hardware subsystems were developed for the PET. The acquisition rates for 10-bit data under machine-language control range from 15 to 25 kHz, but under high-level (BASIC) language-control drop to about 100 Hz.
6. E. D. Salin,.; Gary Horlick, 1980, Signal-to-noise ratio performance characteristics of an inductively coupled plasma, Anal. Chem., 52(11), 1578-82.
[abstract]
Analyte emission signal-to-noise ratio characteristics of an inductively coupled plasma were measured as a function of several ICP experimental variables. Above the detection limit, the standard deviation of the analyte emission signal is linearly related to signal level indicating that analyte flicker is the dominant noise source. It is shown that under such conditions, analyte signal-to-noise ratios are not strongly dependent on plasma power and plasma (coolant) gas flow rate. The emission intensities of Ca, Sr, and Ar were measured as a function of time to assess the potential utility of internal standardization. The emission fluctuations in Ca and Sr are correlated while those of Ca and Ar are not.
5. Eric D. Salin, Gary Horlick, Gary, 1979, Direct sample insertion device for inductively coupled plasma emission spectrometry, Anal. Chem., 51(13), 2284-6.
[abstract]
A sample introduction system that allows the insertion of small amts. of samples (powders, solids, and desolvated liqs.) directly into the inductively-coupled plasma (ICP) has been developed. The sample container is a conventional undercut graphite cup electrode that is mounted inside an ICP torch. Solid and powder samples ranging from 20 mg to <1 mg and liq. samples as small as 5 mL can be analyzed with this system. Preliminary anal. results are presented for aq. and powd. samples contg. nanogram amts. of analyte.
4. Eric D. Salin, J.D. Ingle, Jr., 1979, Construction and performance of a time-multiplex multiple-slit flame atomic fluorescence spectrometer for multi-element analysis, Anal. Chim. Acta, 104(2), 267-78.
[abstract]
The design and performance characteristics of a new multielement flame at. fluorescence spectrometer are presented. Radiation from 4 hollow-cathode tubes is directed onto an unsheathed air-H flame. The resulting at. fluorescence is viewed by a special monochromator with a sep. exit slit for each element. The light exiting from all slits is directed to a single photomultiplier tube. The fluorescence signals from different elements are distinguished by a time multiplex approach. Single-element detection limits for 10 elements and multielement detection limits for 4 elements are presented. The degrdn. of detection limits by flame background emission noise and effect of flame compn. on performance are discussed. Better than 1% precision is obtained for moderate analyte concns.
3. Eric Salin; J. D. Ingle, Jr., 1978, Design and performance of a time multiplex multiple slit multielement flameless atomic absorption spectrometer, Appl. Spectrosc., 32(6), 579-84.
[abstract]
The design and performance characteristics of a new multielement flameless atomic absorption spectrometer are presented. Radiation from four hollow cathode lamps is combined by beam splitters and directed through a Varian model 63 carbon rod atomizer and then into special monochromator with a separate exit slit for each element. The light exiting from all slits is directed to a single photomultiplier tube. Absorbance signals from different elements are distinguished with a time multiplex approach. Data acquisition and presentation is accomplished with a PDP-11 computer system. The absolute light levels are lower than those normally encountered with single element atomic absorption resulting in signal shot noise limited measurements. Detection limits (in ppb) of 0. 2 (Cd), 2 (Mn), and 8 (Pb) were determined under multielement conditions.
2. Eric D. Salin, J.D. Ingle, Jr., 1978, Design and construction of a time multiplex multiple slit multielement flame atomic absorption spectrometer, Anal. Chem., 50(13), 1737-44.
[abstract]
A multielement spectrometer has been developed for the simultaneous determination of four elements by flame atomic absorption (AA). The spectrometer is based on a multiple exit slit monochromator and uses a mirrored funnel to dire light from the various exit slits to a single photomultiplier. A single element hollow cathode (HC) lamp is used for each element and the beams from these HCs are combined by beam splitters. HC lamp pulsing and data acquisition are implemented with a time multiplex approach. The HC lamp pulsing is controlled by simple digital circuitry which sequentially pulses each HC lamp and digitally integrates HC and background signals for each element at a 12. 5 Hz rate for up to 240 cycles. The system presently allows the simultaneous determination of any four of ten possible elements. There are no moving parts during operation and the instrument requires little more hardware than necessary for a conventional single element AA.
1. Eric D. Salin.; J. D. Ingle., Jr., 1978, Performance of a time multiplex multiple slit multielement flame atomic absorption spectrometer, Anal. Chem., 50(13), 1745-52.
[abstract]
The performance characteristics of a new multielement flame atomic absorption (AA) spectrometer are presented. Compared to a conventional single element AA, the absolute light levels measured are considerably lower and additional spectral overlap problems arise. These differences do not significantly affect detection limits, sensitivities, precision, and calibration curves in most cases. Detection limits (in ppb) of 50 (Au), 8 (Cd), 40 (Co), 9 (Cu), 60 (Fe), 2 (Mg), 5 (Mn), 50 (Ni), 50 (Pb), and 20 (Zn) were obtained under favorable multielement conditions and are within a factor of two of detection limits obtained on a good quality commercial single element AA operating with comparable spectral bandpass and integration time. The relative measurement precision at moderate absorbances is typically 1% or better.
Top
Non-Refereed Papers
9. David Duford, Josiane P. Lafleur, Rebecca Lam, Cameron D. Skinner, E.D. Salin. Mercury Determination: A Hair Raising Experiment. McGill Science Undergraduate Research Journal (2006), 1(1), 11-15.
8. Wayne Branagh and Eric D. Salin, 1995, Reshaping the Monolith: The Autonomous Instrument Project, Spectroscopy (Eugene, Oregon) ,10(7) 20-24.
7. E.D. Salin, 1983, Laboratory Computers and Chemical Education, Amer. Lab, 96-101.
6. E.D. Salin, 1982, Laboratory computer acquisition considerations, Part One: software considerations, Amer. Lab, 80-86.
5. E.D. Salin, 1982, Laboratory computer acquisition considerations, Part Two: Language selection, Amer. Lab, 35-38.
4. E.D. Salin, 1982, Laboratory computer acquisition considerations, Part Three: components and support hardware, Amer. Lab, 105-112.
3. E.D. Salin, 1982, Laboratory computer acquisition considerations, Part Four: Computer system peripherals, Amer. Lab, 129-134.
2. E.D. Salin, 1982, Laboratory computer network concepts, Amer. Lab, 151-156.
1. B.J. Gour-Salin and E.D. Salin, 1982, A single computer multi-instrument network, Amer. Lab, 110-116.
Top