title: Simultaneous determination of mercury speciation in biological materials by GC/CVAFS after ethylation and room-temperature precollection.
abstract: We developed a method for the simultaneous determination of monomethyl mercury (MMHg), inorganic mercury [Hg(II)], and total mercury (THg) in biological materials. A variety of biological materials can be digested in methanolic KOH solution. The MMHg and Hg(II) present are converted to volatile ethyl derivatives, methylethyl mercury and diethyl mercury, by an aqueous-phase ethylation reaction with sodium tetraethylborate. The ethyl derivatives are precollected onto a trapping column at room temperature, in case of disconnection with the separation/detection system, and then thermally desorbed into a packed isothermal gas chromatography (GC) column. Eluted organo-Hg compounds from the GC column are decomposed into Hg0, and detection is completed by cold vapor atomic fluorescence spectrometry (CVAFS). Pure standard solutions can be used for calibration. The sum of MMHg and Hg(II) obtained by this method equals the THg value obtained by digestion with HNO3 and H2SO4, reduction with SnCl2, and single-stage amalgamation/CVAFS for all biological materials studied. Absolute detection limits are 0.6 pg and 1.3 pg of Hg as MMHg and Hg(II), respectively, corresponding to 0.3 ng and 0.6 ng/g (wet) of sample.
authors.affiliation: Brooks Rand, Ltd., Seattle, WA 98107.
authors.forename: L
authors.initials: L
authors.lastname: Liang
authors.forename: N S
authors.initials: NS
authors.lastname: Bloom
authors.forename: M
authors.initials: M
authors.lastname: Horvat
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000737:chemistry; D001881:Borates; D002849:Chromatography, Gas / Q000706:statistics & numerical data; D005399:Fishes; D006197:Hair / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides; D017669:Mercury Compounds / Q000032:analysis*; D000432:Methanol; D008767:Methylmercury Compounds / Q000032:analysis; D009132:Muscles / Q000737:chemistry; D017680:Potassium Compounds; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000706:statistics & numerical data
chemical_list: D001881:Borates; D006878:Hydroxides; D017669:Mercury Compounds; D008767:Methylmercury Compounds; D017680:Potassium Compounds; C080440:sodium tetraethylborate; C029943:potassium hydroxide; D000432:Methanol