基于Nafion膜的柱层析纯化过程的电化学在线检测器

电化学检测一般需加入电解质以降低溶液电阻,为解决天然药在层析纯化检测中无支持电解质的问题,研制了一种以液体石蜡石墨为工作电极的电化学在线检测器,利用了Nafion N-324膜固体酸的性质,在不额外添加电解质的情况下,直接获得了杨梅素80％乙醇溶液(V/V)的循环伏安图.在恒电位0.53 V下,实现了对层析液中有效物质的电化学在线检测.在2×10-5～1×10-2 mol/L范围内,峰面积(A)与杨梅素浓度(C)存在线性关系.线性方程为A=2.7227C+0.4341.r=0.9976.在恒电位0.62 V无支持电解质的80％乙醇溶液中,对30％竹叶黄酮粗提品纯化过程的在线检测,获得了时间-电流信号的流出曲线,可用于实际样品分析.

Online Electrochemical Chromatography Detector Based on Nafion Membrane

Electrolyte is always added to decrease the resistance of solution during the electrochemical detection.An online electrochemical detector based on paraffin-graphite powder electrode was deve-loped,because the chromatographic detection of active ingredients of natural medicine usually has no electrolyte.The cyclic voltammograms of myricetin(80%,V/V) ethanol-water as mobile phase) is obtained directly without any additional electrolyte by utilizing the solid acid characteristic of nafion N-324 membrane in this micro-gap flow cell.Peristaltic pump stimulates the chromatographic process,and then it realizes the online detection of eletroactive substances in the eluent at 0.53 V.Peak area is linear with the Myricetin concentration between 0.2 ×10-4 and 10×10-4 mol/L,and the linear equation is A=2.7227C+0.4341,r=0.9976.Furthermore,this detector achieves the online detection of 30% AOB(antioxidant of bamboo leaves) purified by macro porous resin without any supporting electrolyte in 80%(V/V) ethanol-water at 0.62V,and the amperometric i-t curve during the purification process is presented.As a result,this detector can be developed for application.