Selenium Speciation in Biological Samples Using a Hyphenated Technique of High-performance Liquid Chromatography and Inductively Coupled Plasma Mass Spectrometry

A hyphenated technique for chemical speciation analysis of selenium in biological samples is established. A reversed-phase ion-pair high-performance liquid chromatography is introduced for separating seleno-compounds, and meanwhile, an inductively coupled plasma mass spectrometry is combined for online elemental determination. Several standard compounds are used for the qualitative and quantitative analysis of the seleno-compounds, whereas seven selenium-containing compounds, such as SeO42−, SeO32−, TmSe+, SeCys, SeUr, SeMet, and SeCM, can be individually detected. Their detection limits are in the range of 0.1–1.5 μg/l, and the linear calibration for the Se concentrations is in the range of 1 to 100 μg/l. The technique is also applied to analyze human liver cytosolic extracts, human serum, and human urine. Only 50 μl of the samples are needed, and the recoveries of the spiked seleno-compounds are between 93% and 117%. The hyphenated method possesses the merits of simple operation, high sensitivity, and good reproducibility and is a feasible method for speciation analysis of small molecular seleno-compounds in different biological samples.