毛细管电泳方波安培检测法研究

Square-wave Amperometric Detection for Capillary Electrophoresis

报道了一种新型 CE-ECD检测技术方波安培检测法 (Square wave amperometric detection,SWAD) ,并结合柱端检测方式应用于毛细管电泳中 .SWAD采用在恒定电压上叠加一小振幅方波交流电压 ,测量方波后期通过电解池的交流电流而进行定量分析 .以神经递质多巴胺和肾上腺素作为分离检测对象 ,详细讨论了方波频率、方波振幅、平衡电位、分离高压以及毛细管内径等因素对分离检测结果的影响 .实验结果表明 ,SWAD具有良好的抗分离高压影响的能力 ,同时对于微 Pt和 Au等金属工作电极表现了良好的稳定性和重现性 .CE-SWAD对多巴胺的检出限达到 1 .0× 1 0 -7mol/L(S/N=3 )

A square-wave amperometric detection(SWAD) method for capillary electrophoresis(CE) using end-column detection was investigated. An alternating square-wave potential instead of a constant potential previously used was adapted on the working electrode and the alternating current was sampled as the analytical signal. The effect of square-wave amplitude, frequency, initial voltage and the influence of high separation voltage on the S/N ratio were discussed in detail. The advantages of SWAD over the other reported methods using constant potential amperometric detection were of higher stability and reproducibility of the metal working microelectrode and remarkable sensitivity in the reversible electrode process. A detection limit of 1×10 -7 mol/L(S/N=3) was obtained for dapamine.