Analytical methods, general Elemental content

Atomic absorption spectrometry (AAS) is a relatively new analytical technique among the spectroscopic methods. As described in the previous chapters, AAS gives high sensitivity, precision and accuracy along with experimental convenience and a wide instrumental availability. Therefore, this technique has been extensively employed for the analysis of marine samples. However, the elemental contents of marine samples are generally very low, and suitable preconcentration procedures are required. Recent development of graphite-furnace techniques and gas generation techniques has extended the applicability of AAS to marine analysis. The determination of Cd, Cu, Ni, Pb, Hg, As, Sb, Se, Sn and Te has become much easier as a result of the development of these techniques. 

Long-term reproducibility is the prime quality of an analytical method used for the study of stability. Stability must be performed on the element or substance to be certified. Extrapolations on the stability of tracers are of little interest. If the uncertainty of the method for an analyte is poor, even for large sample intakes, the analyst must refer to the experience on similar materials with higher contents or to the general chemical properties of the substance or element. In any other situations certification may be impossible. Such difficulties are mainly encountered in organic or organo-metallic analysis. Experience has shown that some substances may be stable in a matrix but unstable in another even similar one [46-47]. All analytical methods suffer from long term reproducibility. In some cases analysts have developed tools and tricks to minimise this effect. 

This chapter includes sections on The Analytical Method, Sampling and Sample Treatment, Separation and Concentration, Method Classification, and Determinative Methods. The principal thrust of this chapter is a general summary of some of the more common and current analytical methodologies employed for the determination of total elemental contents in a wide variety of biological and environmental materials. Coverage here is general the reader is referred to other chapters in this book for particular details on individual elements covered there and to the many publications referred in this chapter. The chapter... 

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