College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063, P R China.
Electrophoresis. 2010 Jan;31(4):688-94. doi: 10.1002/elps.200900565.
We have employed a high-sensitivity off-line coupled with on-line preconcentration method, cloud-point extraction (CPE)/cation-selective exhaustive injection (CSEI) and sweeping-MEKC, for the analysis of malachite green. The variables that affect CPE were investigated. The optimal conditions were 250 g/L of Triton X-100, 10% of Na(2)SO(4) (w/v), heat-assisted at 60 degrees C for 20 min. We monitored the effects of several of the CSEI-sweeping-MEKC parameters - including the type of BGE, the concentrations of SDS, the injection length of the high-conductivity buffer, and the injection time of the sample - to optimize the separation process. The optimal BGE was 50 mM citric acid (pH 2.2) containing 100 mM SDS. In addition, electrokinetic injection of the sample at 15 kV for 800 s provided both high separation efficiency and enhanced sweeping sensitivity. The sensitivity enhancement for malachite green was 1.9 x 10(4) relative to CZE; the coefficients of determination exceeded 0.9928. The LOD, based on an S/N of 3:1, of CSEI-sweeping-MEKC was 0.87 ng/mL; in contrast, when using off-line CPE/CSEI-sweeping-MEKC the sensitivity increased to 69.6 pg/mL. This proposed method was successfully applied to determine trace amounts of malachite green in fish water samples.
我们采用了一种高灵敏度的离线耦合在线浓缩方法，即浊点萃取（CPE）/阳离子选择性完全注射（CSEI）和胶束电动色谱（MEKC），用于分析孔雀石绿。考察了影响 CPE 的变量。优化条件为：Triton X-100 为 250 g/L，Na2SO4 为 10%（w/v），加热至 60°C 20 min。我们监测了几种 CSEI-胶束电动色谱（MEKC）参数的影响，包括 BGE 的类型、SDS 的浓度、高导电性缓冲液的注入长度和样品的注入时间，以优化分离过程。最佳 BGE 为含 100mM SDS 的 50mM 柠檬酸（pH2.2）。此外，在 15kV 下对样品进行电动注入 800s，可获得高分离效率和增强的洗脱灵敏度。与 CZE 相比，孔雀石绿的灵敏度提高了 1.9×10^4；决定系数均超过 0.9928。基于信噪比为 3:1，CSEI-胶束电动色谱的 LOD 为 0.87ng/mL；相比之下，离线 CPE/CSEI-胶束电动色谱的灵敏度提高到 69.6pg/mL。该方法成功应用于测定鱼水样中的痕量孔雀石绿。
