Speciation of mercury by ionic liquid-based single-drop microextraction combined with high-performance liquid chromatography-photodiode array detection.
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.
Pena-Pereira
Francisco
F
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.
Lavilla
Isela
I
Bendicho
Carlos
C
Vidal
Lorena
L
Canals
Antonio
A
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
D005035:Ethylmercury Compounds; D052578:Ionic Liquids; D008767:Methylmercury Compounds; D010663:Phenylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury