Simultaneous determination of Hg(II) and alkylated Hg, Pb, and Sn species in human body fluids using SPME-GC/MS-MS

A GC/MS-MS method for the determination of Hg(II) and alkylated Hg, Pb, and So species in human urine is described. Separation and identification of t he metal species are performed by capillary gas chromatography coupled with an ion-trap mass spectrometer with electron impact ionization in the tande m-MS mode. For sample preparation a very promising technique was applied th at is based on a derivatization with sodium tetraethylborate followed by he adspace solid phase microextraction (SPME). Operation of the used ion trap in the tandem-MS mode yields in improved detection limits because of a sign al-to-noise ratio that is at least one order of magnitude better than in th e MS mode. The detection limits in real matrices like urine are between 7 a nd 22 ng/L for all species investigated. Urinary levels of inorganic Hg in non-occupationally exposed persons with and without dental amalgam were fou nd to be between 0.1 and 1.4 mu g/L. A reference material ("ClinRep, Level I") was used for quality assurance. Compared to the coupling of GC with ICP -MS ("inorganic" MS), the advantage of the proposed method using an "organi c" MS is that (i) the species can be directly identified via their precurso r and daughter ions and (ii) analysis can be performed with a commercially available hyphenated technique at moderate costs and needs no lab-made inte rfacing. Moreover, it offers a real multi-element/multi-species capability with low detection limits and a minimum of sample preparation.