Fractional Determination of Dissolved Selenium Compounds of Trimethylselenonium Ion, Selenium(IV) and Selenium(VI) in Environmental Water Samples

Abstract

Fractional determination of trimethylselenonium ion(TMSe), Se(IV) and Se(VI) in water samples was studied by graphite furnace atomic absorption spectrometry. After coexisting cations formed a complex with thiosulfate to prevent being adsorbed on cation-exchange resin, separation and concentration of TMSe were carried out by column chromatography on Dowex 50 W-X8 resin. For concentration of inorganic selenium (Se(IV), Se(VI)) in water samples, column chromatography was carried out with an anion-exchange column using Dowex 1-X4 resin and the selenium were eluted simultaneously with 1M hydrochloric acid. Se(IV) in the eluent was extracted with dithizone solution under the condition of 4M hydrochloric acid. Se(VI) could be extracted with dithizone solution after the reduction to Se(IV) with hydroxylamine hydrochloride. In this procedure, the recovery of selenium was in the ragne of 86-102.8%, and the variation coefficient was 4.2-11.3%. The detection limit of TMSe was 10ng/21 and that of Se(IV) and Se(VI) was 5ng/l.