Furnace electrothermal atomizer

Fuel Analysis by Filter Furnace Electrothermal Atomic Absorption Spectrometry... 

Fast on-line/at process sulfur determination, 137 Filter furnace electrothermal atomic absorption spectrometry, 59 Fluoride, 232... 

Note. This table presents a comparison of graphite furnace AAS with the use of a graphite furnace (electrothermal atomizer) as the sample vaporization step in conjunction with ICP-MS and ICP-OES. The solution detection limit, the sample volume, and the absolute detection limit in picograms are given for each technique. The isotope measured is specified for the ICP-MS technique the isotope number has no meaning for the AAS or ICP-OES results. 

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... 

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)... 

ELECTROTHERMAL ATOMIZATION IN GRAPHITE FURNACE A KINETIC MODEL WITH TWO INDEPENDENT SOURCES... 

ScHiFFER U, Krivan V (i999) A graphite furnace electrothermal vaporization system for inductively coupled plasma atomic emission spectrometry. Anal Chem 70 482-490. 

Cimadevilla et al. [691] compared wall, platform, and graphite furnace probe atomisation techniques in electrothermal atomic absorption spectrometry for the determination of ig/l levels of silver, cadmium, and lead in seawater. 

Bruland et al. [122] have shown that seawater samples collected by a variety of clean sampling techniques yielded consistent results for copper, cadmium, zinc, and nickel, which implies that representative uncontaminated samples were obtained. A dithiocarbamate extraction method coupled with atomic absorption spectrometry and flameless graphite furnace electrothermal atomisation is described which is essentially 100% quantitative for each of the four metals studied, has lower blanks and detection Emits, and yields better precision than previously published techniques. A more precise and accurate determination of these metals in seawater at their natural ng/1 concentration levels is therefore possible. Samples analysed by this procedure and by concentration on Chelex 100 showed similar results for cadmium and zinc. Both copper and nickel appeared to be inefficiently removed from seawater by Chelex 100. Comparison of the organic extraction results with other pertinent investigations showed excellent agreement. 

Nonflame atom reservoirs have been developed for specific atomic spectrometric techniques. Electrothermal atomizers (carbon rods, carbon furnaces, or tantalum ribbons) have been developed for AAS or AFS since they require the generation of ground state atoms, whereas... 

All metals at trace concentration, or in trace quantities, can be analyzed by atomic absorption (AA) spectrophotometry in flame or graphite furnace (electrothermal reduction) mode. A rapid, multi-element analysis may use... 

G. Cobo, M. Gomez, C. Camara, M.A. Palacios, Determination of fluoride in complex liquid matrices by electrothermal atomic absorption spectrometry with in-furnace oxygen-assisted ashing, Mikrochim. Acta 110 (1993) 103-110. 

A spectrometer with rapid response electronics should be used for electrothermal atomization, as it must follow the transient absorption event in the tube. Automatic simultaneous background correction (see Section 2.2.5.2) is virtually essential, as non-specific absorption problems are very severe. It is important that the continuum light follows exactly the same path through the furnace as the radiation from the line source (assuming a deuterium lamp is being used rather than Smith-Hieftje or Zeeman effect). The time interval between the two source pulses should be as short as possible (a chopping frequency of at least 50 Hz) because of the transient nature of the signal. 

Electrothermal atomization is particularly useful when the amount of sample is very small, when very low levels of detection are required and when the matrix is dilute or volatile. These criteria often apply to clinical samples (a pin-prick sample of blood produces only 50-100 mm of whole blood, but this is sufficient for analysis using an electrothermal atomizer, hence it is not essential for an intravenous sample to be taken). For such samples, often pretreatment is not required, and body fluids and biological tissues can be ashed in situ in the furnace. This also applies to some foods, although others may need some preliminary wet ashing. 

The literature on applications of electrothermal atomizers is now extremely large and, because of the details of the furnace programmes used, is well worth consulting. The tables in the Atomic Spectrometry Updates reports (see Appendix C) offer the best way of accessing this information. 

Describe a typical electrothermal atomizer for atomic absorption spectrometry. Critically compare graphite furnaces, air-acetylene flames, and nitrous oxide flames as atom cells for atomic absorption spectrometry. 

GD, 112-113,113(f) dark space, 112 Grimm source, 112 sputtering, 112 Glow discharge. See GD Graphite furnace. See Electrothermal atomizers Gratings. 

Figure 21-10 Reduction of interference by using a matrix modifier, (a) Graphite furnace temperature profile for analysis of Mn in seawater, (b) Absorbance profile when 10 xL of 0.5 M reagent-grade NaCl is subjected to the temperature profile in panel a. Absorbance is monitored at the Mn wavelength of 279.5 nm with a bandwidth of 0.5 nm. (c) Reduced absorbance from 10 nl of 0.5 M NaCl plus 10 of 50 wt% NH4NO3 matrix modifier. [From M. N. Quigley and F. Vernon, "Matrix Modification Experiment lor Electrothermal Atomic Absorption Spectrophotometry." J. Chem. Ed. 1996, 73. 980.]...

Conventional AA instruments (Figure 1) use a flame atomization system for liquid sample vaporization. An air-acetylene flame (2300°C) is used for most elements. A higher temperature nitrous oxide-acetylene flame (2900°C) is used for more refractory oxide forming elements. Electrothermal atomization techniques such as a graphite furnace can be used for the direct analysis of solid samples. 

Using palladium-magnesium nitrate mixtures as chemical modifiers, Hinds and Jackson [114] effectively delayed the atomisation of lead until atomic absorption spectrometer furnace conditions were nearly isothermal. This technique was used to determine lead in soil slurries. Zhang et al. [115] investigated the application of low-pressure electrothermal atomic absorption spectrometry to the determination of lead in soils. 

AMS = accelerated mass spectroscopy EDTA = ethylene diamine tetra acetic acid GFAAS = graphite furnace atomic absorption spectrometry ICP-AES = inductively coupled plasma - atomic emission spectroscopy NAA = neutron activation analysis ETAAS = electrothermal atomic absorption spectrometry SEC/ICP-MS = size-exclusion chromatography/ICP-AES/mass spectrometry HLPC/ICP-AES = high-performance liquid chromatography/ICP-AES LAMMA = laser ablation microprobe mass analysis NA = not applicable ppq = parts per quadrillion... 

Notes HG-AAS, Aydride generation atomic absorption spectrometry HG-AFS, /tydride generation atomic fluorescence spectrometry FI-CV-AAS, flow-injection cold-vapor atomic absorption spectrometry FAAS,flame atomic absorption spectrometry GF-AAS, graphite furnace atomic absorption spectrometry and ET-AAS, electrothermal atomic absorption spectrometry. 

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