Yan Xiu-Ping, Yin Xue-Bo, Jiang Dong-Qing, He Xi-Wen
State Key Laboratory of Functional Polymer Materials for Adsorption and Separation, and Central Laboratory, Research Center for Analytical Sciences, College of Chemistry, Nankai University, Tianjin 300071, China.
Anal Chem. 2003 Apr 1;75(7):1726-32. doi: 10.1021/ac026272x.
A novel method for speciation analysis of mercury was developed by on-line hyphenating capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS). The four mercury species of inorganic mercury Hg(II), methymercury MeHg(I), ethylmercury EtHg(I), and phenylmercury PhHg(I) were separated as mercury-cysteine complexes by CE in a 50-cm x 100-microm-i.d. fused-silica capillary at 15 kV and using a mixture of 100 mmol L(-1) of boric acid and 12% v/v methanol (pH 9.1) as electrolyte. A novel technique, hydrostatically modified electroosmotic flow (HSMEOF) in which the electroosmotic flow (EOF) was modified by applying hydrostatical pressure opposite to the direction of EOF was used to improve resolution. A volatile species generation technique was used to convert the mercury species into their respective volatile species. A newly developed CE-AFS interface was employed to provide an electrical connection for stable electrophoretic separations and to allow on-line volatile species formation. The generated volatile species were on-line detected with AFS. The precisions (RSD, n = 5) were in the range of 1.9-2.5% for migration time, 1.8-6.3% for peak area response, and 2.3-6.1% for peak height response for the four mercury species. The detection limits ranged from 6.8 to 16.5 microg L(-1) (as Hg). The recoveries of the four mercury species in the water samples were in the range of 86.6-111%. The developed technique was successfully applied to speciation analysis of mercury in a certified reference material (DORM-2, dogfish muscle).
通过在线联用毛细管电泳（CE）与原子荧光光谱法（AFS），开发了一种汞形态分析的新方法。无机汞Hg(II)、甲基汞MeHg(I)、乙基汞EtHg(I)和苯基汞PhHg(I)这四种汞形态，在一根50 cm×100μm内径的熔融石英毛细管中，以15 kV的电压，使用100 mmol L⁻¹硼酸和12% v/v甲醇的混合物（pH 9.1）作为电解质，通过CE分离为汞-半胱氨酸络合物。采用了一种新技术，即静水压改性电渗流（HSMEOF），通过施加与电渗流方向相反的静水压来改性电渗流，以提高分离度。使用了一种挥发性物种发生技术，将汞形态转化为各自的挥发性物种。采用新开发的CE-AFS接口，提供电连接以实现稳定的电泳分离，并允许在线形成挥发性物种。产生的挥发性物种通过AFS进行在线检测。四种汞形态的迁移时间精密度（RSD，n = 5）在1.9 - 2.5%范围内，峰面积响应精密度在1.8 - 6.3%范围内，峰高响应精密度在2.3 - 6.1%范围内。检测限范围为6.8至16.5μg L⁻¹（以Hg计）。水样中四种汞形态的回收率在86.6 - 111%范围内。所开发的技术成功应用于一种有证标准物质（DORM-2，鲨鱼肌肉）中汞的形态分析。
