title: Certification of methylmercury content in two fresh-frozen reference materials: SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis).
abstract: This paper describes the development of two independent analytical methods for the extraction and quantification of methylmercury from marine biota. The procedures involve microwave extraction, followed by derivatization and either headspace solid-phase microextraction (SPME) with a polydimethylsiloxane (PDMS)-coated silica fiber or back-extraction into iso-octane. The identification and quantification of the extracted compounds is carried out by capillary gas chromatography/mass spectrometric (GC/MS) and inductively coupled plasma mass spectrometric (GC/ICP-MS) detection. Both methods were validated for the determination of methylmercury (MeHg) concentrations in a variety of biological standard reference materials (SRMs) including fresh-frozen tissue homogenates of SRM 1946 Lake Superior fish tissue and SRM 1974a organics in mussel tissue (Mytilus edulis) and then applied to the certification effort of SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis). While past certifications of methylmercury in tissue SRMs have been based on two independent methods from the National Institute of Standards and Technology (NIST) and participating laboratories, the methods described within provide improved protocols and will allow future certification efforts to be based on at least two independent analytical methods within NIST.
authors.affiliation: Hollings Marine Laboratory, Analytical Chemistry Division, National Institute of Standards and Technology (NIST), 331 Fort Johnson Road, Charleston, SC, 29412, USA. clay.davis@nist.gov
authors.forename: W Clay
authors.initials: WC
authors.lastname: Davis
authors.forename: S J
authors.initials: SJ
authors.lastname: Christopher
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Pugh
authors.forename: O F X
authors.initials: OF
authors.lastname: Donard
authors.forename: Eva A
authors.initials: EA
authors.lastname: Krupp
authors.forename: David
authors.initials: D
authors.lastname: Point
authors.forename: Milena
authors.initials: M
authors.lastname: Horvat
authors.forename: D
authors.initials: D
authors.lastname: Gibicar
authors.forename: Z
authors.initials: Z
authors.lastname: Kljakovic-Gaspic
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Porter
authors.forename: Michele M
authors.initials: MM
authors.lastname: Schantz
mesh_terms: D000818:Animals; D002849:Chromatography, Gas / Q000379:methods; D005399:Fishes; D005506:Food Contamination; D005615:Freezing; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D008460:Meat / Q000032:analysis; D008767:Methylmercury Compounds / Q000032:analysis*; D049880:Mytilus edulis / Q000737:chemistry*; D012016:Reference Values; D017747:Seafood / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods; D014131:Trace Elements / Q000032:analysis*; D014481:United States
chemical_list: D008767:Methylmercury Compounds; D014131:Trace Elements