Electrothermal Atomic Absorption Spectrometry ETAAS

Schierle and Otto [63] used a two-layer perceptron with error back-propagation for quantitative analysis in ICP-AES. Also, Schierle et al. [64] used a simple neural network [the bidirectional associative memory (BAM)] for qualitative and semiquantitative analysis in ICP-AES. 

In the multivariate calibration field, Khayatzadeh et al. [65] compared ANNs with PLS to determine U, Ta, Mn, Zr and W by ICP in the presence of spectral interferences. For ANN modelling, a PCA preprocessing was found to be very effective and, therefore, the scores of the first five dominant PCs were input to an ANN. The network had a linear transfer function on both the hidden and output layers. They used only 20 samples for training. 

An ANN was used by Magallanes et al. [66] to optimise hydride generation-inductively coupled plasma atomic emission spectrometry (HG-ICP-AES) coupling for the determination of Ge at trace levels. 

Catasus et al. [67] studied two types of neural networks traditional multilayer perceptron neural networks and generalised regression neural networks (GRNNs) to correct for nonlinear matrix effects and long-term signal drift in ICP-AES. 

The recoveries of several rare earth elements in leachates obtained from apatite concentrates were determined by Jorjani et al. [68] for ICP-AES and ICP-MS. A neural network model was used to predict the effects of operational variables on the La, Ce, Y and Nd recoveries in the leaching process. The neural network employed was a feed-forward one. 

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Miscellaneous. Trace analyses have been performed for a variety of other materials. Table 9 Hsts some uses of electrothermal atomic absorption spectrometry (etaas) for determination of trace amounts of elements in a variety of matrices. The appHcations of icp /ms to geological and biological materials include the following (165) ... 

M. J. Cal-Prieto, M. Felipe-Sotelo, A. Carlosena, J. M. Andrade, P. Lopez-Mahia, S. Muniategui and D. Prada, Slurry sampling for direct analysis of solid materials by electrothermal atomic absorption spectrometry (ETAAS). A literature review from 1990 to 2000, Talanta, 56, 2002, 1-51. 

I. Arambarri, R. Garcia and E. Millan, Application of experimental design in a method for screening sediments for global determination of organic tin by electrothermal atomic absorption spectrometry (ETAAS), Fresenius J. Anal. Chem., 371(7), 2001, 955-960. 

S. Ch. Nielsen, S. Sturup, H. Spliid and E. H. Hansen, Selective flow injection analysis of ultra-trace amounts of Cr(VI), preconcentration of it by solvent extraction and determination by electrothermal atomic absorption spectrometry (ETAAS), Talanta, 49(5), 1999, 1027-1044. 

The sequential extraction of chromium from soils has been studied [89]. A three-step sequential extraction scheme has been proposed using acetic acid, hydroxylamine hydrochloride and ammonium acetate as extracting agents. Steps 1 and 2 were measured by electrothermal atomic absorption spectrometry (ETAAS). Step 3 was measured by flame atomic absorption spectrometry. Interfering effects when measuring chromium in soils were circumvented through the use of a 1% 5-hydroxyquinoline suppressor agent. 

Spectrometric techniques based on atomic absorption or the emission of radiation flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma-optical emission spectrometry (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), and cold vapor (CV)/hydride generation (HG), mainly for trace and ultratrace metal determinations. 

Electrothermal atomic absorption spectrometry (ETAAS) was in the past, and still is in the present, the most useful technique for total aluminum determination in biological samples. The technique is subject to contamination from dust, but by keeping the instrument under laminar flow conditions or setting the sample in the autosampler just before pipetting, contamination may be avoided. In recent years, chromatographic techniques have also been... 

Flame Atomic Absorption Spectrometry (FAAS) Electrothermal Atomic Absorption Spectrometry (ETAAS) e.g. Graphite Furnace Atomic Absorption Spectrometry (GFAAS) Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Anodic Stripping Voltammetry (ASV)... 

As mentioned before, two interlaboratory studies were organised prior to certification, involving ca. 15 laboratories using techniques such as cold vapour atomic absorption spectrometry, direct current plasma atomic emission spectrometry (DCP-AES), differential pulse anodic stripping voltammetry (DPASV), microwave plasma atomic emission spectrometry (MIP-AES), electrothermal atomic absorption spectrometry (ETAAS) and neutron activation analysis with radiochemical separation (RNAA). 

Electrothermal atomic absorption spectrometry (ETAAS) also called graphite furnace atomic absorption spectrometry (GFAAS) for the... 

Atomic absorption spectrometry Electrothermal atomic absorption spectrometry (ETAAS) is at present the most commonly used technique for the determination of silicon in biological fluids. Owing to the formation of refractory silicon carbide and volatile silicon oxide compounds during the atomization cycle in the graphite tube. 

During the last decade a number of investigations have been directed towards direct analysis of air particulate matter without using sampling on filters. This approach includes either direct injection of air or use of impactor directly in the furnace to be applied as atomizer in electrothermal atomic absorption spectrometry (ETAAS) or electrostatic precipitation of metals in aerosols on a tungsten collecting electrode which afterwards is put in the electrothermal atomizer (Cresser et al., 1988 1992). 

In order to evaluate possible hazards for the enviroiunent and human health it is crucial to develop analytical strategies for fast and easy quantification of traces and ultra-traces of Pd in environmental matrices as well as biological tissues and fluids. Despite the efforts of numerous workgroups, a reliable method for the determination of Pd in all environmental matrices has yet to be developed. Up to date, the most important analytical methods for this task are electrothermal atomic absorption spectrometry (ETAAS), inductively coupled plasma-mass spectrometry (ICP-MS) and isotope dilution (ID)-ICP-MS, also strategies involving inductively coupled plasma-atomic emission spectrometry (ICP-AES), and electrochemical methods like anodic stripping voltammetry (ASV) have been described. Furthermore, total reflection X-ray fluorescence (TXRF) and instrumental neutron activation analysis (INAA) have been successfully employed for the determination of PGE in enviromnental matrices. 

Manjusha, R., Dash, K., and Karunasagar, D., UV-photolysis assisted digestion of food samples for the determination of selenium by electrothermal atomic absorption spectrometry (ETAAS), Food Chem., 105, 260-265, 2007. 

Several spectroscopic methods have been used to monitor the levels of heavy metals in man, fossil fuels and environment. They include flame atomic absorption spectrometry (AAS), atomic emission spectroscopy (AES), graphite furnace atomic absorption sp>ectrometry (GFAAS), inductively coupled plasma-atomic emission sp>ectroscopy (ICP/AES), inductively coupled plasma mass spectrometry (ICP/MS), x-ray fluorescence sp>ectroscopy (XRFS), isotope dilution mass spectrometry (IDMS), electrothermal atomic absorption spectrometry (ETAAS) e.t.c. Also other spectroscopic methods have been used for analysis of the quality composition of the alternative fuels such as biodiesel. These include Nuclear magnetic resonance spectroscopy (NMR), Near infrared spectroscopy (NIR), inductively coupled plasma optical emission spectrometry (ICP-OES) e.t.c. 

After preconcentration, these samples can then be back-extracted into a similar solvent or into a matrix that is more compatible with the detection system. The use of SIA with bead injection was demonstrated for the preconcentration of nickel and bismuth on a cation-exchange resin prior to detection by electrothermal atomic absorption spectrometry (ETAAS) or ICP-MS. 

Direct measurements of several trace metals by electrothermal atomic absorption spectrometry (ETAAS) have been reported. In general, sensitivities are inadequate for open-ocean waters, though in more metal-enriched environments (e.g., coastal waters and sediment pore waters) such analysis is possible careful corrections for the large and complex salt effects are necessary. The interferences can be minimized by the use of appropriate chemical modifiers, platforms in the graphite tubes, and sophisticated background correction schemes such as Zeeman. 

Electrothermal atomic absorption spectrometry (ETAAS) has also been used for the determination of trace elements in biological samples because of its speed, minimum need for sample preparation, possibility of automation, and good sensitivity. However, ETAAS measurements are susceptible to matrix effects and therefore require standards similar to the samples. In addition. 

AAS is the most widely used analytical technique for the determination of lead in biological materials [57,58], The majority of AAS methods employ the electrothermal atomic absorption spectrometry (ETAAS) technique, using either Zeeman background correction or deuterium background correction for the determination of lead in biological fluids [55,59-65], Urine is less often employed as an indicator of exposure however, similar problems associated with AAS determination of lead exist for blood as well as urine (1) incomplete atomization (2) volatile lead salts (3) spectral interferences (4) buildup of carbonaceous residue reducing sensitivity and precision. These analytical problems are eliminated by optimal sample preparation, e,g., dilution, addition of matrix modifiers, deproteinization, and background correction and calibration by matrix-matched standards [66],... 

Recent developments include inductively coupled plasma emission spectrometry (ICP), electrothermal atomic absorption spectrometry (ETAAS), and spectrofluorimetric methods. 

Electrothermal atomic absorption spectrometry (ETAAS) has been the single most important technique in advancing our knowledge of the transition metal distribution in seawater. The graphite-furnace mode is used most frequently. It has the advantage of high sensitivity and therefore small sample volume (e.g., 10-50//L). Major disadvantages are the matrix interferences which usually necessitate a pre-concentration and/or a separation step (see Sections 12.2.1 and 12.2.2). Another application of ETAAS is the cold-vapour technique for the determination of mercury (Section 12.2.4). 

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