Sample preparation and HPLC separation approaches to speciation analysis of selenium in yeast by ICP-MS

C. Casiot (1) , Joanna Szpunar (1, 2) , Ryszard Lobinski (2) , Martine Potin-Gautier (1, 2)

1 LCABIE - Laboratoire de Chimie Analytique Bio-Inorganique et Environnement
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

Eight solid-liquid extraction procedures were evaluated for the recovery of selenium species from yeast. Speciation of Se in the extracts was characterized by different types of HPLC, including size-exclusion, anion-exchange and reversed-phase chromatography with ICP-MS detection. The results obtained depended critically on the sample preparation procedure used. Leaching with water and with methanol led only to 10-20% recoveries of Se, split into eight compounds, among which Se(IV) and selenomethionine could be identified. Leaching with pectinolytic enzymes released an additional 20% of selenomethionine. Leaching with sodium dodecyl sulfate solution allowed the solubilization of a selenoprotein that accounted for ca. 30% of the total Se present. Leaching with proteolytic enzymes led to recoveries of Se above 85%, the majority as selenomethionine. Hydrolysis of the yeast with tetramethylammonium hydroxide solubilized the sample completely but the Se species present were entirely degraded to selenomethionine and inorganic selenium. A sequential leaching procedure is proposed for the evaluation of selenium speciation in yeast without the need for a coupled technique.

Domaines: Chimie analytique

C. Casiot, Joanna Szpunar, Ryszard Lobinski, Martine Potin-Gautier. Sample preparation and HPLC separation approaches to speciation analysis of selenium in yeast by ICP-MS. Journal of Analytical Atomic Spectrometry, 1999, 14 (4), pp.645--650. ⟨10.1039/a809027k⟩. ⟨hal-01559778⟩