title: Speciation of mercury by ionic liquid-based single-drop microextraction combined with high-performance liquid chromatography-photodiode array detection.
abstract: Room temperature ionic liquids can be considered as environmentally benign solvents with unique physicochemical properties. Ionic liquids can be used as extractant phases in SDME, being compatible with chromatographic systems. A single-drop microextraction method was developed for separation and preconcentration of mercury species (MeHg(+), EtHg(+), PhHg(+) and Hg(2+)), which relies on the formation of the corresponding dithizonates and microextraction of these neutral chelates onto a microdrop of an ionic liquid. Afterwards, the separation and determination were carried out by high-performance liquid chromatography with a photodiode array detector. Variables affecting the formation and extraction of mercury dithizonates were optimized. The optimum conditions found were: microextraction time, 20 min; stirring rate, 900 rpm; pH, 11; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]); drop volume, 4 microL; and no sodium chloride addition. Limits of detection were between 1.0 and 22.8 microg L(-1) for the four species of mercury, while the repeatability of the method, expressed as relative standard deviation, was between 3.7 and 11.6% (n=8). The method was finally applied to the determination of mercury species in different water samples.
authors.affiliation: Departamento de Química Analítica y Alimentaria, Area de Química Analítica, Facultad de Química, Universidad de Vigo, Campus As Lagoas-Marcosende s/n, 36310 Vigo, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Pena-Pereira
authors.forename: Isela
authors.initials: I
authors.lastname: Lavilla
authors.forename: Carlos
authors.initials: C
authors.lastname: Bendicho
authors.forename: Lorena
authors.initials: L
authors.lastname: Vidal
authors.forename: Antonio
authors.initials: A
authors.lastname: Canals
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005035:Ethylmercury Compounds / Q000032:analysis; D052578:Ionic Liquids; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D008767:Methylmercury Compounds / Q000032:analysis; D010663:Phenylmercury Compounds / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D005035:Ethylmercury Compounds; D052578:Ionic Liquids; D008767:Methylmercury Compounds; D010663:Phenylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury