Fan Zhefeng, Liu Xuejuan
Department of Chemistry, Shanxi Normal University, Gongyuan Street No. 1, Linfen 041004, China.
J Chromatogr A. 2008 Feb 8;1180(1-2):187-92. doi: 10.1016/j.chroma.2007.12.010. Epub 2007 Dec 8.
A novel method for determination of methylmercury (MeHg) and phenylmercury (PhHg) by liquid-liquid-liquid microextraction (LLLME) coupled with capillary electrophoresis (CE) with ultraviolet (UV) technique was developed. The method based on MeHg and PhHg was complexed with 1-(2-pyridylazo)-2-naphthol (PAN) to form hydrophobic complexes. When the sample solution was stirred, analytes were extracted into the organic layer (200 microL toluene) and back-extracted simultaneously into the 4.0 microL 0.1% (w/v) l-cysteine microdrop. The factors affecting on the LLLME of two mercury species, including sample pH, complex reagent concentration, extraction time, volume of organic solvent, stirring rate and phase volume ratio, were investigated. Under the optimized conditions, the detection limits (S/N=3) of MeHg and PhHg were 0.94 and 0.43 ngmL(-1) (as Hg), respectively. The precisions (RSDs, c=10 ngmL(-1), n=7) were in the range of 3.3-3.4% for migration time, 6.1-7.2% for peak area response, and 6.7-7.5% for peak height response for the two mercury species. The enrichment factors of 324 for MeHg and 210 for PhHg were obtained with 40 min LLLME. The developed method was successfully applied to the determination of trace amounts of MeHg and PhHg in water samples.
建立了一种液-液-液微萃取（LLLME）结合毛细管电泳（CE）和紫外（UV）技术测定甲基汞（MeHg）和苯基汞（PhHg）的新方法。该方法基于MeHg和PhHg与1-（2-吡啶偶氮）-2-萘酚（PAN）络合形成疏水络合物。在搅拌样品溶液时，分析物被萃取到有机层（200μL甲苯）中，同时被反萃取到4.0μL 0.1%（w/v）L-半胱氨酸微滴中。研究了影响两种汞形态LLLME的因素，包括样品pH值、络合试剂浓度、萃取时间、有机溶剂体积、搅拌速率和相比。在优化条件下，MeHg和PhHg的检测限（S/N=3）分别为0.94和0.43 ngmL⁻¹（以Hg计）。两种汞形态的迁移时间精密度（RSDs，c=10 ngmL⁻¹，n=7）在3.3-3.4%范围内，峰面积响应在6.1-7.2%范围内，峰高响应在6.7-7.5%范围内。通过40分钟的LLLME，MeHg的富集因子为324，PhHg的富集因子为210。所建立的方法成功应用于水样中痕量MeHg和PhHg的测定。
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