Graphite furnace atomic absorption spectrometers

Brinckman and coworkers [54] introduced an automated interface connecting a high pressure liquid chromatograph to a graphite furnace atomic absorption spectrometer. A specially designed well sampler is placed into the appropriate location of a stopped autosampler carousel. The column effluent enters the well sampler from the bottom and leaves through the side duct connected to a water aspirator. The autosampler 

Without an autosampler, an interface can be constructed from an eight-port, two-position sample valve with sample and by-pass loops of appropriate volumes, an injection device that delivers aliquots of the column effluent isolated in the sample loop into the graphite furnace, and electronic control and switching circuitry that allows all steps in the analysis to occur in the correct sequence [55, 56]. All the components of the interface are commercially available. The injection device must 

Direct-current and inductively coupled plasma emission spectrometers 

Comparison of graphite furnace atomic absorption and inductively coupled argon plasma emission spectrometers as element-specific detectors for liquid chromatography 

Financial support for the work on arsenic-specific detectors and for the preparation of this publication by the Robert A. Welch Foundation of Houston, Texas is gratefully acknowledged. 

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Dabeka, R. W. and McKenzie, A. D. (1991). Graphite furnace atomic absorption spectromet-ric determination of selenium in foods after sequential wet digestion with nitric acid, dry ashing and coprecipitation with palladium. Can. J. Appl. Spectrosc. 36,123-126. 

Andreae [564] coprecipitated tellurium (V) and tellurium (VI) from seawater and other natural waters with magnesium hydroxide. After dissolution of the precipitate with hydrochloric acid, the tellurium (IV) was reduced to tellurium hydride in 3 M hydrochloric acid. The hydride was trapped inside the graphite tube of a graphite furnace atomic absorption spectrometer, heated to 300 °C, and tellurium (IV) determined. Tellurium (VI) was reduced to tellurium (IV) by boiling with hydrochloric acid and total tellurium determined. Tellurium (VI) was then calculated. The limit of detection was 0.5 pmol per litre and precision 10-20%. 

Huang and Shih [616] used a graphite furnace atomic absorption spectrometer with a stabilised platform furnace involving atomisation from a graphite surface pretreated with vanadium to determine down to 24 ppt of zinc in seawater. 

Table 1.3 Available flame and graphite furnace atomic absorption spectrometers... 

U. Heitmann, M. Schutz, H. Becker-Ross and S. Florek, Measurements on the Zeeman-splitting of analytical lines by means of a continuum source graphite furnace atomic absorption spectrometer with a linear charge coupled device array, Spectrochim. Acta Part B, 51, 1996, 1095-1105. 

Azzaria and Aftabi [ 149] showed that stepwise (as compared to continuous) heating of soil samples before determination of mercury by atomic absorption spectrometry gives increased resolution of the different phases of mercury. A gold-coated graphite furnace atomic absorption spectrometer has been used to determine mercury in soils [150]. 

Other analytical tools have also been used as offline detectors for the FFF techniques. Bio et al. (1995) used for this purpose a graphite furnace atomic absorption spectrometer (GFAAS) to analyze colloidal kaolin particles. Contado et al. (1997) used same design to characterize river-suspended particulate matter of size <1 pm. However, the centrifuges available for SdFFF are only capable of separating particles with sizes down to 80 nm. Usage of SdFFF for characterization of HS is therefore restricted because of this limitation. 

Nygren, O., Nilsson, C.-A. and Freeh, W. (1988) On-line interfacing of a liquid chromatograph to a continuously heated graphite furnace atomic absorption spectrometer for element-specific detection. Anal. Chem., 60, 2204-2208. 

To graphite furnace atomic absorption spectrometer Silanized glass wool... 

Much more sensitive and less time-consuming techniques such as mass spectrometry, atomic emission, and atomic absorption are needed for the analysis of pollutants. Detectors such as graphite furnace-atomic absorption spectrometer (GF-AAS), inductively coupled plasma-mass spectrometer (ICP-MS), or inductively coupled plasma-atomic emission spectrometer (ICP-AES) seem to be ideal candidates for the analysis of trace metals because of their very low detection limits. The high temperatures used avoid the need for tedious digestions in many samples. FFF-gas chromatography-mass spectrometry could perhaps be used in the analysis of particular organic molecules. 

Miller-Ihli N. J. (1989) Automated ultrasonic mixing accessory for slurry sampling into a graphite furnace atomic absorption spectrometer, J Anal At Spectrom 4 295-297. 

D. Chakraborli, D.C.J. Hillman, K.J. Irgolic, and R.A. Zingaro, Hitachi Zeeman graphite furnace atomic absorption spectrometer as a selenium-specific detector for ion chromatography. Separation and determination of selenite and selenate, j. Chromatogr., 249,81,1982. 

After being dried, the samples were reexamined by nitrogen sorption and mercury intrusion, and a portion of the material was analyzed to determine the residual mercury levels. This analysis was achieved by acid digestion (10 mL of 50% aqua regia sample sizes were approximately 0.2 g in all cases) in pressure-sealed poly(tetrafluoroethylene) (PTFE) tubes heated to 140 °C for 10 min in a microwave oven (CEM). The solutions were analyzed after suitable dilution in distilled water with a graphite furnace atomic absorption spectrometer (Perkin Elmer 5100-PC). The detection limit for this method is estimated to be 6 ppm of mercury on the dry solid. 

Fig. 10.9 Automatic control of a graphite-furnace atomic absorption spectrometer by means of a microcomputer. (Reproduced from [13] with permission of Elsevier).

GFAAS Graphite furnace atomic absorption spectrometer (analytical... 

M.-S. Chan and S.-D. Huang. Direct determination of cadmium and copper in seawater using a transversely heated graphite furnace atomic absorption spectrometer with Zeeman-effect background corrector. Talanta 51 373-380, 2000. 

Electrothermal atomisation (graphite furnace) atomic absorption spectrometer with a device for correcting background absorption. 

Direct and simultaneous determination of copper, chromiiun, aliuninium, and manganese in mine with a multielement graphite furnace atomic absorption spectrometer, Anal. Chem. 

The conductivity detector was set at a sensitivity that would have produced an acceptable signal for the selenium compounds in the absence of the other ions. Because of the high sensitivity setting on the detector and the high concentrations of chloride, sulfate, and phosphate relative to selenite and selenate, the recorder pen is off the chart for retention times between 8 and 25 minutes, and signals for selenite and selenate cannot be reliably located. However, when a graphite furnace atomic absorption spectrometer was employed as the selenium-specific... 

Fig. 2.2. Ion chromatograms of a synthetic river water (277 mg chloride, 69 mg sulfate, 5 mg 1 phosphate) spiked with 400 micrograms selenium as selenite and 400 micrograms selenium as selenate recorded with a conductivity detector and a Hitachi Zeeman graphite furnace atomic absorption spectrometer (GFAAS) as the selenium-specific detector (Dionex Model 16 ion chromatograph, 1.0 ml sample, 50 x 3 mm anion precolumn Dionex 30008 mobile phase 0.008 M aqueous Na2C03, 0.46 ml min 150 X 3 mm anion separator column Dionex 30589 250 x 3 mm anion suppressor column Dionex 30066. GFAAS drying 120°, 60 sec no ashing atomization 2500°, 6 sec Se lamp 10 niA, 196.0 nm 80 sec between injections retention time in min). Redrawn from the Journal of Chromatography [9] by permission of Elsevier Science Publishers and the authors.

Fig. 2.6. High pressure liquid chromatography-graphite furnace atomic absorption spectrometer system with well sampler and autosampler as interface [A dead volvime screw B sample well C side duct connected to aspirator for withdrawal of liquid]. Redrawn from the Journal of Chromatographic Science (54] by permission of Preston Publications, a division of Preston Industries, Inc., and the authors.

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