DEVELOPMENT, VALIDATION, AND APPLICATION OF A METHOD FOR QUANTIFICATION OF METHYLMERCURY IN BIOLOGICAL MARINE MATERIALS USING DAS CHROMATOGRAPHY ATOMIC-EMISSION DETECTION

A gas chromatographic method was developed for the quantification of a lkylmercury species using microwave-induced plasma atomic emission det ection (GC-AED), The column conditioning and analyte derivatization re quired for previous methods were found to be unnecessary for stable, a ccurate, and sensitive element-specific detection using GC-AED, Chroma tographic and detection parameters such as stationary phase type, stat ionary phase film thickness, GC column dimensions, helium mobile phase column head pressure, detector makeup gas now rate, and detector reag ent gas type and now rate were found to significantly affect analyte r esponse, The detection limit for the optimized GC-AED conditions was 0 .8 pg (0.1 pg/s) of methylmercury chloride (as mercury), A solid-liqui d extraction procedure with preparative gel permeation chromatography cleanup and GC-AED analysis was used to quantify methylmercury in a va riety of complex matrix marine materials, The methylmercury quantifica tion method was validated: with four marine certified reference materi als (CRMs). The method was then applied to 13 standard reference mater ials, CRMs, and control materials for which no certified reference val ues for methylmercury have been determined, Four National Institute of Standards and Technology Standard Reference Materials and one control material, which were analyzed using the GC-AED method, were also anal yzed by two other laboratories using independent methods to further va lidate the method.