title: Liquid chromatographic--cold vapour atomic fluorescence spectrometric determination of mercury species.
abstract: Solvent extraction, sonication, and microwave-assisted extractions in the presence of extraction agents (thioacetic acid, citric acid, cysteine, 2-mercaptoethanol, HCl + NaCl, etc.) were tested for the isolation of mercury species. A mixture of 6 M HCl and 0.1 M NaCl was selected as the most suitable extraction agent. The extraction efficiency was about 10% higher and the RSD below 3.3% when microwave-assisted extraction was applied instead of sonication. The liquid chromatography-cold vapour atomic fluorescence spectrometry (LC/CV-AFS) method was optimised and used for separation and determination of inorganic mercury cations and alkylated and arylated mercury species. Isocratic elution at a flow rate of 0.15 mL/min (with a mobile phase containing 0.05% 2-mercaptoethanol (pH = 5) and 7% methanol and with a stepwise increase of methanol content up to 100% MeOH in the 15th min) was used for separation of mercury species on a Hypersil BDS C18 RP column. The limits of detection of the LC/CV-AFS system were estimated as 0.2 microg/L (3%) for MeHg+, 0.07 microg/L (5.3%) for inorganic Hg, 0.06 microg/L (3.4%) for PhHg+, and 0.12 microg/L (4.4%) for EtHg with the corresponding RSDs at 5 microg/L (n = 10) given in parentheses. The concentrations (2-10 mg/kg fresh weight) of total mercury and methylmercury (90-99% of the total mercury) in selected fish obtained by HPLC/CV-AFS were in good agreement (absolute deviations 0.05 mg/kg) but more precise (RSDs <5.4% at 5 mg/L, n = 10) than those determined by GC coupled to an electron capture detector. The RSDs (3.1-8.2% and 4.1-9.0%) of the overall analytical procedure for the determination of total mercury (AMA 254) and methylmercury (HPLC/CV-AFS) were determined for intra-day and inter-day assays, respectively.
authors.affiliation: Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Brno, Czech Republic.
authors.forename: Pavlina
authors.initials: P
authors.lastname: Houserová
authors.forename: David
authors.initials: D
authors.lastname: Matejícek
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Kubán
authors.forename: Jana
authors.initials: J
authors.lastname: Pavlícková
authors.forename: Josef
authors.initials: J
authors.lastname: Komárek
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D005399:Fishes / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis; D007287:Inorganic Chemicals / Q000032:analysis; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis; D008872:Microwaves; D009941:Organomercury Compounds / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D007287:Inorganic Chemicals; D008767:Methylmercury Compounds; D009941:Organomercury Compounds; D008628:Mercury