Atomic emission spectroscopy evaluation

EPA. 1986b. Inductively coupled plasma atomic emission spectroscopy—method 6010. In Test methods for evaluating solid waste. 3rd ed. SW-846. Washington, DC U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response. 

On the other hand, a chemical approach (microscopic) is developed for the evaluation of the recombination coefficient y using atomic emission spectroscopy (actinometry) on the same device and in the same temperature range but only at 200 Pa total air pressure. Finally, the activation energy of atomic oxygen recombination can be reached for all the ceramics. 

A number of methods exist for the determination of parts-per-billion (ng/g) levels of chromium in aqueous media (Table 8.1). These are repeatedly reviewed as new techniques are introduced (4,5,6). Potentially all these techniques could be applied to petroleum samples after matrix destruction, but in practice, only a few have been utilized. After wet oxidation of a large sample (> 100 g), 10 to 50 fig of chromium may be determined by a colorimetric procedure with 1,5-diphenylcarbohydrazide after iron, copper, molybdenum, and vanadium are extracted as the cup-ferrates (3). In survey analyses, Cr levels as low as 5 ng/g have been measured by optical emission spectroscopy after ashing (2,3) or directly by neutron activation with extended irradiation and counting times (1). Concentrations of chromium above 100 ng/g in used lubricating oils have been measured directly by flame atomic absorption (8) for lower concentrations, heated vaporization atomic absorption (HVAA) has been utilized (9). In the Trace Metals Project, two procedures using this latter technique were evaluated for the determination of 10 ng Cr/g in a variety of petroleum matrices. 

Applications considerations are included in many chapters in Vol 3 of Dean and Rains (1975) devoted to the determination of specific elements, and in various natural and manufactured materials. Methods for analytical atomic spectroscopy, 8th edition (ASTM 1987) contains a wealth of information based on evaluation and approval deliberations by the respected ASTM, including various computation practices, general laboratory practices, practices and methods for analysis of metallurgical and inorganic materials by spectrochemical techniques including flame atomic emission. Dawson et al. (1993) have published a tutorial review on background and background correction in analytical atomic emission spectrometry. 

This study was conducted for the purpose of evaluating atomic absorption and flame emission spectroscopy for the routine quantitative analysis of large numbers of water samples for elements present in quantities ranging from large to trace amounts. 

Atomic fluorescence is the most recent development in analytical atomic spectroscopy thus it has not had time to be evaluated as well as other techniques. Further developments in this field with respect to optimizing sources and sample cells, together with improvements in instrumental parameters and development of readily available commercial instrumentation, should lead to this technique serving in the area of analytical spectral methods to supplement the already well-established arc and spark emission, flame emission, and atomic absorption spectroscopy. 

FIGURE 10-37. Calibration curves of atomic absorption signals of zinc using absorbance and percentage absorption versus zinc concentration in /ig/ml. [From W. G. Schrenk, Evaluation of Data, in Flame Emission and Atomic Absorption Spectroscopy, Vol. 2, Edited by J. A. Dean and T. C. Rains, Marcel Dekker, New York (1971), Chap. 12. Used by permission of Marcel Dekker, Inc.]... 

As an example of a spectrum obtained with a 10 m instrument (grating radius 10m) a recording of the carbon K emission line from the CO2 molecule is shown in Fig.5.7. As can be seen, the high resolution reveals a clear structure due to molecular vibration. Through careful analysis of a spectrum of this kind it is possible to evaluate the C-O bond length very accurately in the core-ionized molecule. It turns out that the bond length is shortened by about 2% when the Is core vacancy has been formed in the carbon atom. From the linewidth it is also possible to evaluate the natural lifetime of the C Is state (Sect.9.4.5). The lifetime is of the order 10" s. Atomic structure research using X-ray emission spectroscopy has been discussed in [5.9-13]. 

For colloids with a physically adsorbed surfactant or cca, the adsorption isotherm is important. The adsorbant concentration on the particle surface can be measured by infrared spectroscopy using diffuse reflectance and by ESCA. Absolute concentrations are difficult to determine with ESCA on "rough" surfaces, and a calibration point is required with other techniques. The change of the concentration of adsorbant in solution after adsorption on the colloid surfaces can be detected by elemental analysis of supernatant with plasma emission or atomic absorption if adsorbant contains specific element(s). When colloids are sterically stabilized, the effectiveness of the stabilization can be evaluated with solvent-nonsolvent techniques and with temperature studies ( 25,26). 

His laboratory is concerned with the analysis of a wide range of materials which include a variety of biological specimens, mineral samples, air particulate matter, and water samples. The information obtained is used to evaluate various individual and environmental problems. Two of the techniques which have been used for water analysis are atomic absorption (J, 4) and flame emission (2) spectroscopy, and a study of factors aflFecting these methods is described here. The samples came from a number of sources which included well water and city water. Consequently, the concentration ranges of some of the elements were quite wide. Five determinations were made daily on both the samples and standards for each element over a period of several months to provide suflBcient data for an adequate evaluation of precision. At present, ten elements (Na, K, Ca, Mg, Zn, Pb, Mn, Cu, Fe, and Ni) are being determined quantitatively. 

Evaluation of accuracy requires comparing results against standard materials or the results obtained using other independent techniques. Figure 11.9 illustrates the correlation for iron in orchard leaves determined by atomic-absorption, DC-arc, and x-ray-fluorescence spectroscopy, and ICP-emission spectrometry. The standard deviations are also indicated. 

E.J. dos Santos, A.B. Herrmann, M.A. Vieira, V.L.A. Frescura, and A.J. Curtius. Evaluation of slurry preparation procedures for the determination of mercury by axial view inductively coupled plasma optical emission spectrometiy using on-line cold vajror generation. Spectrochimica Acta Part B Atomic Spectroscopy 60 659-665, 2005. 

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