Studies On Vapor Generation-Atomic Fluorescence Spectrometry In Analyzing Biological Samples

Creatures could adsorb and cumulate the trace elements. Furthermore, they would directly influence the development of human beings as they were the key link in food chain. So, determination of trace elements in biological samples is required to monitor the environmental pollution and there was an important ecological significance for measurement trace elements in creature body, including the toxic elements such as arsenic, antimony and mercury, and necessary nutritive elements like selenium.Vapor generation-atomic fluorescence spectrometry (VG-AFS) is a new analytical technique, coupled with the merits of vapor generation and non-disperse atomic fluorescence spectrometry. The technique has many virtues including simple spectral lines, high sensitivity, fewer interference and multi-elements analysis. At present, VG-AFS has been widely used for the determination of trace elements in geological, environmental and biological fields.In this paper, methods for determination of ultra-trace As, Sb and Se have been established using hydride generation-non-dispersive atomic fluorescence spectrometry based on a pure Ar-H2 flame. And a method for determination of ultra-trace Hg has also been developed in biological sample.As a pure and steady Ar-H2 flame was formed Providing H2 by hydrogen generator, the flame noise and the method detection limit has been reduced greatly. Effects of L-cysteine was studied. The allowable amount of coexisted ion was well increased in the presence of L-cysteine. Detection limit of the method is 0.47ng·g-1 for As, 1.35ng·g-1 for Sb, respectively. The results from several standard reference biological materials agree with certified values. RSD of the method in different samples is respectively 3.59%~9.23% for As, 5.07%~18.63% for Sb.Content of ultra-trace Se in biological samples has been directly measured by HG-AFS, after the sample was digested by closed pressured or wet digestion technique. The pure Ar-H2 flame, which was formed by H2 from hydrogen generator, varies effects of the HCl concentration on signal intensity of selenium. The signal intensity was constant within HCl concentration from 16% to 60%. Additional hydrogen greatly increased the sensitivity of Se, especially in the low acidity. Two kinds of digestion methods are compared. The analytical results are consistent with each other. Detection limit of the method is 0.72ng·g-1. The results from several standard reference biological materials agree with certified values with precision of 2.37%~10.33% RSD.A method has been developed for determination of ultra-trace mercury in biological samples. Hg was assayed by VG-AFS after sample digested by reverse aqua regia. Two kinds of digestion methods both close pressured and wet digestion are compared. Detection limit of the...