Micro-scale preparation and characterization of isotopically enriched monomethylmercury

A synthesis method for the micro-scale laboratory preparation of isotopically enriched monomethylmercury (MMHg) has been successfully established. This compound is an important standard for species-specific isotope dilution analysis. The isotopically enriched MMHg has been synthesized from commercially available mercury oxide ((HgO)-Hg-201) using methylcobalamin coenzyme as methylating agent. The time required is less than 2 h and the final yield is about 90%. The proposed method is faster than those previously reported in the literature. It allows work on a micro scale to control the use of expensive enriched isotope standard. It also allows control of unintentional formation of dimethylmercury. The enriched mercury-containing reaction products were analyzed by capillary gas chromatography coupled to an inductively coupled plasma mass spectrometer after derivatization with sodium tetraethylborate. The isotopic composition, concentration, purity and stability of the synthesized, enriched MMHg have been investigated in order to establish standard protocols for MMHg isotope dilution analysis or isotope labeling incubation experiments. Copyright (C) 2002 John Wiley Sons, Ltd.