Heated graphite atomization atomic

Belsel, W. R. "The Direct Determination of Serum Chromium by an Atomic Absorption Spectrophotometer with a Heated Graphite Atomizer". Anal. Blochem. (1974), 283-292. 

Nowka R, Muller H (1997) Direct analysis of solid samples by graphite furnace atomic absorption spectrometry with a transversely heated graphite atomizer and D2-background correction system (SS GF-AAS). Fresenius J Anal Chem 359 132-137. 

Using a newly developed, transversely heated graphite atomizer and D2-back-ground correction (for details see Sections 2.2 and 4.3), Cd, Pb and Cr were determined in cement and river sediment samples. Of the various calibration approaches applied the best results, also in comparison with wet chemical procedures, were achieved with calibration curves constructed by means of different BCR CRMs with different analyte concentrations and usually n = to individual intakes (Nowka and Muller 1997). 

Several types of atom cell have been used for AAS. Of these, the most popular is still the flame, although a significant amount of analytical work is performed using various electrically heated graphite atomizers. This second type of atom cell is dealt with at length in Chapter 3, and the material here is confined to flames. 

A Perkin Elmer model 503 atomic absorption spectrophotometer, equipped with Perkin Elmer HGA-2100 heated graphite atomizer (Figure 2), a deuterium arc background corrector (12), and a strip chart recorder, was used. The HGA-2100 graphite furnace was purged with argon. Hollow cathode lamps were used except for cadmium for which an electrodeless discharge lamp (Perkin Elmer) was used. 

Atomic absorption spectrometry (AAS) relies on the atomization of substances in an appropriate medium, like a flame, a plasma, or a graphite tube, and the capability of the free atoms to absorb light of a specific wavelength [89]. One of the usual techniques for the determination of trace elements is the heated graphite atomizer (HGA), which consists of a graphite tube connected as a resistor in a high electrical current circuit (Figure 6.22). 

Heated Graphite Atomizer (HGA) is a device used in atomic absorption spectrometry for atomization of compounds in graphite tube, which is connected as a resistor in a high electrical current circuit. 

Figure 3.4. Perkin-Elmer heated graphite atomizer...

Figure 7 Electrothermal tubes available commercially (A) transversely heated graphite atomizer (THGA), (B) longitudinally heated Massmann atomizer. From Ebdon L (1998) Introduction to Analytical Atomic Spectrometry. Reproduced by permission of John Wiley Sons Limited.

Gran plot a linearized form of a titration curve, (p. 293) graphite furnace an electrothermal atomizer that relies on resistive heating to atomize samples, (p. 414) gravimetry any method in which the signal is a mass or change in mass. (p. 233)... 

Instead of employing the high temperature of a flame to bring about the production of atoms from the sample, it is possible in some cases to make use of either (a) non-flame methods involving the use of electrically heated graphite tubes or rods, or (b) vapour techniques. Procedures (a) and (b) both find applications in atomic absorption spectroscopy and in atomic fluorescence spectroscopy. 

Graphite bisulfates are formed by heating graphite with a mixture of sulfuric and nitric acids. In the reaction, the graphite planes are partially oxidized. There is approximately one positive charge for every 24 carbon atoms, and the HS04 anions are distributed between the planes, (a) What effect is this oxidation likely to have on the electrical conductivity (b) What effect would you expect it to have on the x-ray diffraction pattern observed for this material Refer to Major Technique 3 on x-ray diffraction, which follows this set of exercises. 

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