Speciation of organic selenium compounds by high-performance liquid chromatography-inductively coupled plasma mass spectrometry in natural samples
Abstract
The importance of selenium in the environment and in biological systems is now well recognized. Its biochemical functions, e.g., its anti-oxidant role and therefore cell protecting function, as an essential constituent of the enzyme glutathione peroxidase, has provoked a growing interest in the determination of this element. Selenoamino acids are essential for the understanding of the biogeochemical cycle of Se and TMSe+ is a known urinary metabolite present at high levels when Se is taken in excess. In this work we present a hyphenated technique (HPLC-ICP-MS) available for the separation of the organic Se compounds (selenocystine, selenomethionine and trimethylselenonium ion). The choice of column and solvents has been a critical parameter. Good repeatability and excellent detection limits (less than 1 μg l-1 for each species) have been reached for standard solutions and the application to some natural samples (enriched yeast, human serum and urine) has shown quite promising results.