title: Species-specific GC/ICP-IDMS for trimethyllead determinations in biological and environmental samples.
abstract: An accurate and sensitive species-specific isotope dilution GC/ICPMS method was developed for the determination of trimethyllead (Me3Pb+) in biological and environmental samples. A trimethyllead spike was synthesized from 206Pb-enriched metallic lead by reaction of lead halide with methyllithium and subsequent formation of trimethyllead iodide. The isotopic composition of the spike solution was determined by GC/ICPMS after derivatization with tetraethylborate, and its concentration was determined by reverse isotope dilution analysis. The species-specific GC/ICP-IDMS method was validated by reference material CRM 605 (urban dust) certified for Me3Pb+. The method was also applied to determine the Me3Pb+ content in six biological reference materials (DORM 2, CRM 278, CRM 422, CRM 463, CRM 477, MURST-ISS-A2) and one sediment reference material (CRM 580) for which no certified values of this species exist. The Me3Pb+ concentrations in the biological reference materials vary in the range of 0.3-17 ng g(-1) (as Pb) except for the Antarctic Krill (MURST-ISS-A2), where the concentration was less than the detection limit of 0.09 ng g(-1), which was also found for the sediment. Up to 20% of total lead was methylated in the biological reference materials, whereas much higher methylation fractions were found for mercury. The method was also applied to seafood samples purchased from a supermarket with Me3Pb+ concentrations in the limited range of 0.3-0.7 ng g(-1). On the contrary, the portion of methylated lead in these samples varied over more than 2 orders of magnitude from 0.02 to 7.5%.
authors.affiliation: Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55099 Mainz, Germany.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Poperechna
authors.forename: Klaus G
authors.initials: KG
authors.lastname: Heumann
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D004391:Dust / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D007201:Indicator Dilution Techniques; D007554:Isotopes; D007854:Lead; D017747:Seafood / Q000032:analysis; D013756:Tetraethyl Lead / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D004391:Dust; D004785:Environmental Pollutants; D007554:Isotopes; D013756:Tetraethyl Lead; D007854:Lead; C039474:trimethyllead