Multielement determination with atomic

Simultaneous Multielement Determinations by Atomic Absorption and Atomic Emission with a Computerized Echelle Spectrometer/Imaging Detector System... 

Atomic emission spectroscopy with inductive coupled exitation (ICP-AES), although quite costly, is important for multielement determination with high sample rate. Neutron activation analysis (NAA) is a powerful detection method but costly in terms of both financial and work expenditures. X-ray fluorescence (XRF) methods are perfect multielement methods with high sampling rate. ICP-MS is also applied. 

Depth profile of elements in seawater near hydrothermal vents. [From T. Akagi and H. Haraguchi, Simultaneous Multielement Determination of Trace Metals Using W mL of Seawater by Inductively Coupled Plasma Atomic Emission Spectrometry with Gallium Coprecipitation and Microsampling Technique Anal. Chem. 1990, 62.81.]... 

Comparisons with other systems. Data presented in Table VI provide a comparison of results obtained with the image dissector with results reported by others with other systems. Results in the second column represent multielement detection limits observed in this work. Results in the third and fourth columns represent detection limits reported for single element determinations with conventional optics and a silicon vidicon (12J and a commercial atomic absorption instrument (33). 

All detection limits are given in micrograms per liter and were determined using elemental standards in dilute aqueous solution. All detection limits are based on a 98% confidence level (3 S.D.). All atomic absorption (Model 5100) detection limits were determined using instrumental parameters optimized for the individual element, including the use of system 2 electrodeless discharge lamps where available. ICP emission (Optima 3000) detection limits were obtained under simultaneous multielement conditions with a radial plasma. Detection limits using an axial plasma (Optima 3000 XL) are typically improved by 5-10 times. 

Inductively coupled plasma-atomic emission spectrometry was investigated for simultaneous multielement determinations in human urine. Emission intensities of constant, added amounts of internal reference elements were used to compensate for variations in nebulization efficiency. Spectral background and stray-light contributions were measured, and their effects were eliminated with a minicomputer-con-trolled background correction scheme. Analyte concentrations were determined by the method of additions and by reference to analytical calibration curves. Internal reference and background correction techniques provided significant improvements in accuracy. However, with the simple sample preparation procedure that was used, lack of sufficient detecting power prevented quantitative determination of normal levels of many trace elements in urine. 

Coherent forward scattering (CFS) atomic spectrometry is a multielement method. The instrumentation required is simple and consists of the same components as a Zeeman AAS system. As the spectra contain only some resonance lines, a spectrometer with just a low spectral resolution is required. The detection limits depend considerably on the primary source and on the atom reservoir used. When using a xenon lamp as the primary source, multielement determinations can be performed but the power of detection will be low as the spectral radiances are low as compared with those of a hollow cathode lamp. By using high-intensity laser sources the intensities of the signals and accordingly the power of detection can be considerably improved. Indeed, both Ip(k) and Iy(k) are proportional to Io(k). When furnaces are used as the atomizers typical detection limits in the case of a xenon arc are Cd 4, Pb 0.9, T11.5, Fe 2.5 and Zn 50 ng [309]. They are considerably higher than in furnace AAS. 

To a limited extent atomic absorption spectrometry can also be used for multielement determinations. Several manufacturers introduced systems with multi-... 

Nash et al. (2000) (Methodologies for determination of antimony in terrestrial environmental samples). The review by Tolg (1987) (Extreme trace analysis of the elements -the state of the art today and tomorrow) is an insightful review by an experienced trace analyst concentrating on atomic spec-trometric methods including AAS, OES, XRE, MS with many variants of excitation. A table is provided comparing the capability of determinative methods listing the method, the specific technique, limit of determination, matrix effects, multielement determination, and speciation analysis. Methods compared include AAS, ZAAS, OES-DCP, OES-ICP, OES-MIP, OES-HC, EANES, AES, XRS, MS, NAA, voltammetry, LAS and fluorimetry. 

The adsorption properties of Amberlite XAD4 resins as adsorbents suitable for multielement preconcentration of complexes of 15 elements with different chelate-forming reagents from aqueous solutions have been extensively investigated by Yang and Jackwerth [129,130]. Adsorbed trace compounds can easily be eluted from the resin by use of 1 M HNOj in acetone and subsequently determined by atomic absorption spectrophotometry (AAS). Besides multielement preconcentration, selective trace separation procedures are possible by suitable selection of the complexing reagents and pH adjustment of the sample solution. 

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