title: Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.
abstract: In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Pingjing
authors.initials: P
authors.lastname: Li
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Hu
mesh_terms: D000097:Acetonitriles; D000588:Amines; D000818:Animals; D003545:Cysteine; D019075:Electrophoresis, Capillary / Q000379:methods*; D005399:Fishes; D006197:Hair / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D060106:Lakes; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D008567:Membranes, Artificial; D008628:Mercury / Q000032:analysis*; D009132:Muscles; D009941:Organomercury Compounds / Q000032:analysis*; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000097:Acetonitriles; D000588:Amines; D008567:Membranes, Artificial; D009941:Organomercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury; D003545:Cysteine; C003935:dodecylamine; C032159:acetonitrile