DETERMINATION OF TRACE INORGANIC SELENIUM IN ORGANOSELENIUM (SELENOSUGAR) ORAL NUTRITION LIQUIDS BY GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY WITH HYDRIDE GENERATION

A method has been proposed for the determination of trace levels of in organic selenium in organoselenium (selenosugar) oral nutrition liquid s using hydride generation-graphite furnace atomic absorption spectrom etry (HG-GFAAS), taking advantage of the fact that this organic seleni um compound did not generate volatile hydride upon reduction. K2S2O8 w as selected for the decomposition of the compound in a boiling water b ath. Selenium was found to give a sharp analytical signal upon reducti on with NaBH4 in 1.0 mol L-1 HCl medium. The characteristic mass givin g an integrated absorbance of 0.0044 s was 21 pg. An absolute detectio n limit (3s) of 36 pg was obtained. The recovery was in the range of 9 4.2-102.1%. Less than parts per million levels of inorganic Se in the presence of organic selenium can be determined.