碳糊电极吸附催化伏安法测定决明子中大黄酚

Adsorptive Catalytic Voltammetric Determination of Chrysophanol at Carbon Paste Electrode

在pH9.5的0.52 mol.L-1氨水-氯化铵缓冲溶液中,0 V(vs.SCE)富集60 s,以250 mV.s-1扫描速率线性扫描至-1.0 V。大黄酚在碳糊电极上于-0.61 V处产生一灵敏的吸附催化伏安峰,其峰电流值的二阶导数与大黄酚浓度在2.0×10-10～1.0×10-8mol.L-1范围内呈线性关系,检出限(3S/N)为1.0×10-10mol.L-1。初步探讨了大黄酚在碳糊电极和汞电极上的伏安行为和电极反应机理,此方法用于决明子中大黄酚的测定,并以此样品为基体作回收试验,测得回收率在96.8%～104.8%之间。

In an ammoniacal buffer solution of pH 9.5,and by accumulation at 0 V（vs.SCE） for 60 s scanning linearly from 0 to-1.0 V at the rate of 250 mV·s-1,a sensitive adsorptive catalytic voltammetric peak given by chrysophanol was observed at the carbon paste electrode at the potential of-0.61 V（vs.SCE）.Linear relationship between values of 2nd derivative of peak current and concentration of chrysophanol was obtained in the range of 2.0×10-10-1.0×10-8mol·L-1,with its detection limit（3S/N） of 1.0×10-10mol·L-1.A preliminary discussion on the voltammetric behavior and electrochemical mechanism of electrode reaction of chrysophanol at both the carbon paste electrode and mercury electrode was also given.This method was used in the determination of chrysophanol in sample of seminacassiae,and using this sample as matrix,recovery was tested by standard additon method,giving results of recovery in the range of 96.8% to 104.8%.