QUANTITATIVE-ANALYSIS OF HUMAN HAIR FOR SELENIUM(IV), SELENIUM(VI) AND TOTAL SELENIUM BY HYDRIDE-GENERATION ATOMIC-ABSORPTION SPECTROMETRY

Optimized procedures were established for the determination of total S e, organic Se, Se(IV), and Se(VI) in human hair by means of hydride-ge neration atomic absorption spectrometry (HGAAS), respectively. Using t his method, the total Se content in a hair sample was determined throu gh pretreating the sample with nitric acid-perchloric acid, and then r educing Se(VI) to Se(IV) with 6.0 mol dm(-3) hydrochloric acid; howeve r, for individual Se(IV), Se(VI) or soluble Se, after the hair sample was immersed into water and disrupted ultrasonically for 8 h at room t emperature, 2,3-diaminonaphthalene (DAN) reagent was added to extract Se(IV). The sum of Se(IV) and Se(VI) was determined by extracting Se(I V) after reducing all of the Se(VI) into Se(IV) with the addition of p otassium bromide. Se(VI) was obtained by subtracting Se(IV) from the s um of Se(IV) and Se(VI). The content of organic Se in the hair sample was calculated by subtracting Se(IV)+Se(VI) from the total Se. The det ection limit of the method was 0.3 ngSe cm(-3), and the average precis ion (relative standard deviation) was less than 5% (n=6).