Atomizer graphite tube furnace

Evenson, M. A. and Pendergast, D. D. "Rapid Ultramicro Direct Determination of Erythrocyte Lead Concentration by Atomic Absorption Spectrophotometry with Use of a Graphite Tube Furnace". Clin. Chem. (1974), 20, 163-171. 

The graphite furnace method of atomization utilizes a small graphite tube furnace to electrically heat rapidly a small volume of the analyte solution contained inside to a temperature that eventually causes atomization. 

Even a technique of higher detection power as ET-AAS may require some sort of previous analyte enrichment for difficult elements. In the determination of As and Se in mineral waters described by Hudnik and Gomiscek [23], coprecipitation of both elements on hydrated Fe(III) oxide was employed to improve LoDs, otherwise impaired by matrix effects. A graphite tube furnace was the atomization cell, with the atomic vapor sampled with element electrodeless discharge lamps. After treatment of the sample with Fe(III) solution at the appropriate pH, the oxide precipitate was filtered and dissolved and the solution volume reduced to 5 mL of 0.2 M H2SO4. Ten-microliter volume aliquots of sample and standard solutions were injected into the furnace. Reported LoDs were 0.2 and 0.5 p,g l-1 for As and Se, respectively. 

Sensitivities of Sc, Y and REE elements as obtained with a pyrolytic graphite coated graphite tube furnace using the Hitachi Z-9000 simultaneous multi-element atomic absorption spectrometer and comparison with some... 

In 1955, A. Walsh recognized this and showed how the absorption from the great preponderance of unexcited molecules could be exploited analytically.Thus, in atomic absorption spectroscopy (AAS) the light from a (usually modulated) somce emitting the spectrum of the desired analyte element is passed through a sample atomization cell (such as a flame or graphite tube furnace), a monochromator (to isolate the desired somce emission line) and finally into a detector to allow measmement of the change in somce line... 

Parris and collaborators have described a procedure utilizing a commercial atomic absorption spectrophotometer with a heated graphite tube furnace atomizer linked to a... 

Fig. 57. G raphite atomizers used in atomic spectrometry. (A) Original graphite tube furnace according to MafSmann (a) graphite tube with sampling hide (reprinted with permission from Ref. [172]), (B) carbon-rod atomizer system according to West (a) support (b) clamps (cooled) (c) graphite rod or cup (reprinted with permission from Ref. [175]).

Apart from graphite tube furnaces, both cups and filaments are used as atomizers in electrothermal AAS [271]. The models originally proposed by L vov et al. [171] and by Massmann [172] were described in Section 3.4. In the case of the latter, which is most widely used, the optical beam is led centrally through the graphite tube, which is closed at both ends with quartz viewing ports mounted in the cooled tube holders. Sample aliquots are introduced with the aid of a micropipette or a computer controlled dispenser through a sampling hole in the middle of the tube. 

Grgic, I. and Hudnik, V. (1989) Behaviour of mercury complexes in a graphite tube furnace for atomic absorption spectrometry. Anal. Chim. Acta, 226, 203-211. 

Related to the carbon rod atomizer is the heated graphite tube furnace atomizer. Here, the sample is injected into the center of a graphite tube, which is resistively heated. Welz (W1) reported the determination of blood lead with such a system in which the sample is dried (20 seconds), ashed, and atomized by stepwise increase in the temperature. The precision was poor, though, being 5-10 /xg/100 ml. Norval and Butler (N3) described a graphite tube system for use on any number of atomic... 

Applications The potentials of DL-AAS have been demonstrated by measurement of trace metals in various atom reservoirs such as analytical flames and graphite tube furnaces. The limits of detection are typically two orders of magnitude lower than with... 

L vov platform Platform on which sample is placed in a graphite-tube furnace for atomic spectroscopy to prevent sample vaporization before the walls reach constant temperature. 

Graphite tubes with internal diameters of some 4 mm. wall thickness 1 mm, and a length up to 30-40 mm are mostly used. Filaments enabling the analysis of very small sample volumes and mini-cups of graphite held between two graphite blocks have also been described [111]. When graphite tube furnaces are used for optical spectrometry. the optical path coincides with the axis of the tubes, whereas in filaments and cups, the radiation passes above the atomizer. Furnace currents up to 100 A and potentials of a few volts are... 

Parris et al- -, have described a procedure utilizing a commercial atomic absorption spectrophotometer with a heated graphite tube furnace atomizer linked to a gas chromatograph for the determination of trimethylarsine in respirant gases produced in microbiological reactions. The overall GC-AA system used by these workers is illustrated in Figure 188. 

Electrothermal Atomizers A significant improvement in sensitivity is achieved by using resistive heating in place of a flame. A typical electrothermal atomizer, also known as a graphite furnace, consists of a cylindrical graphite tube approximately... 

Atomic absorption spectroscopy is an alternative to the colorimetric method. Arsine is stiU generated but is purged into a heated open-end tube furnace or an argon—hydrogen flame for atomi2ation of the arsenic and measurement. Arsenic can also be measured by direct sample injection into the graphite furnace. The detection limit with the air—acetylene flame is too high to be useful for most water analysis. 

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