毛细管电泳-电化学发光分离检测辣椒粉中罗丹明B

建立一种以三联吡啶钌(Ru(bpy)32+)为发光体系的毛细管电泳-电化学发光检测系统,并将其应用于分离和测定辣椒粉中的罗丹明B含量。考察检测电压、Ru(bpy)32+溶液浓度、磷酸盐缓冲液的p H值和浓度、分离电压、进样电压与进样时间等因素对分离检测的影响。结果表明:在检测电压1.14 V、Ru(bpy)32+溶液浓度5 mmol/L、磷酸盐缓冲溶液浓度20 mmol/L(p H 8.0)、进样时间10 s、进样电压10 k V、分离电压15 k V条件下,罗丹明B在6 min中得到分离。方法的线性范围为5×10-7~5×10-5 mol/L,检出限为1×10-7 mol/L(RSN=3)。对1.0×10-5 mol/L的罗丹明B标准溶液连续测定5次,迁移时间和峰面积的相对标准偏差分别为3.2%和1.5%。该方法可成功应用于辣椒粉中罗丹明B含量的测定。

Separation and Determination of Rhodamine B in Chili Power by Capillary Electrophoresis with Electrochemiluminescence Detection

A sensitive and simple method based on capillary electrophoresis (CE) with electrochemiluminescence (ECL)
detection has been developed for the separation and determination of rhodamine B in chili power. The effects of detection
potential, the concentration of Ru(bpy)3
2+, the acidity and concentration of the running buffer, separation voltage and
injection time were investigated to acquire the optimum conditions. The detection electrode was a 300 μm diameter platinum
microelectrode at a detection potential of 1.14 V (versus Ag/AgCl). Rhodamine B could be well separated within 6 min in a
50 cm length fused-silica capillary at a separation voltage of 15 kV in a 20 mmol/L PBS buffer (pH 8.0). The response range
of rhodamine B was from 5 × 10-7 to 5 × 10-5 mol/L with a detection limit of 1 × 10-7 mol/L (RSN = 3). The proposed method
demonstrated long-term stability and reproducibility with relative standard deviations (RSD) of less than 3.5% for both
migration time and electrophoretic peak area (n = 5). This method can be successfully applied to the analysis of rhodamine B
in chili power with satisfactory assay results.