聚乙烯吡烙烷酮修饰碳糊电极-双通道毛细管电泳安培法测定环境中的硝基酚

建立了几种硝基酚的聚乙烯吡烙烷酮修饰碳糊电极-双通道毛细管电泳安培检测的新方法.采用双工作电极和两台伏安仪,将样品的检测电位分别设定在氧化电位(+0.5V_vs.SCE)和还原电位(-1.4V_vs.SCE),在一个检测池中同时获得所有样品的氧化和还原信息,以还原电流和氧化电流值之比(Nc=ir/io)作为定性依据,对样品的纯度进行确证.通过优化工作电极、检测电位、缓冲溶液、β-CD和乙醇浓度等实验参数,实现了几种硝基酚的分离检测,同时采用样条小波最小二乘法对样品数据信号进行处理,并将此法应用于实际样品的测定.

Determination of Nitrophenols of Environment by Dual-electrode and Dual-channel Electrochemical Detection of Capillary Electrophoresis with Polyvinylpyrrolidone Modified Carbon Paste Electrode

A new method for determination of nitrophenols was presented based on polyvinylpyrrolidone modified carbon paste electrode coupled to a dual-electrode and dual-channel electrochemical detection system of capillary electrophoresis. In this system, two working electrodes and two amperometric detector were employed. The oxidative and reductive detection potentials were set at +0.5 V and -1.4 V vs. SCE, respectively. The ratio of reductive and oxidative current response(Nc=ir/io) obtained at each electrode was also used to verify sample purity. Four nitrophenols were determined with oxidation and reduction at the same time. Efficient, rapid and versatile electrophoretic conditions were obtained with 25 mmol/L Tris-2.85 mmol/L citric acid-10 mmol/L β-CD-10% ethanol. The effects of the working electrode, detection potential, buffer, the concentration of β-CD and ethanol on the separation were investigated. The output signal was processed by spline wavelet least square, which can extract useful information from high noise signals. The method was applied to separation and determination of sample of environment with satisfactory results.