Quantitative analysis of volatile selenium metabolites in normal urine by headspace solid phase microextraction gas chromatography–inductively coupled plasma mass spectrometry

The combination of headspace–solid phase microextraction (HS–SPME) and gas chromatography–inductively coupled plasma mass spectrometry (GC–ICPMS) was evaluated for the determination of volatile selenium metabolites in normal urine samples, i.e. without selenium supplementation. HS–SPME operating conditions were optimised and a sampling time of 10 min was found to be suitable for simultaneous extraction of dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). The amount of DMSe and DMDSe extracted onto fibre coating was calculated in clean matrix, i.e. Milli-Q water, on the basis of depletion experiments. When applied to normal urine samples, the developed method allowed the detection of four volatile selenium containing species, among which DMSe and DMDSe could be quantified by standard additions.