Abstract
Selenium is a chalcogen element belonging to the same group 16 on the periodic table as oxygen and sulfur. It is an essential element in animals but can become highly toxic beyond the nutritional level. Naturally occurring organic and inorganic Se species ingested from food can be utilized for the syntheses of selenoproteins, and are transformed into the common intermediate, selenide (Se2-). Se2- interacts with a thiol group to form selenopersulfide (-S-Se-), and is further transformed to selenophosphate which is a Se-donor for the selenoprotein synthesis. Although various methods for the detection of Se compounds have been reported, a quantitative analysis of Se2- and these reactive Se compounds have not been achieved. In this study, a quantitative and selective chemico-analytical method was established to quantify the Se2- and reactive Se compounds, i.e., reactive selenium species (RSeS), in animal tissues by LC-ICP-MS with a chemical derivatization. For the derivatization of selenide, 2,5-dibromoadipic acid was employed as an alkylating agent, and tetrahydroselenophene-2,5-dicarboxylic acid was synthesized as a standard compound of the derivatization. The reaction conditions for the derivatization and the detection conditions of LC-ICP-MS were investigated. After the optimization of the experimental conditions, we tried to quantify Se2- and RSeS in rat tissues under various nutritional conditions. Our technique allowed us the quantitative detection of selenide and other RSeS in the rat tissues. We continuously tackle to apply the technique to various biological samples.
