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目的:研究大黄酚玻碳电极上的电化学行为;建立测定大黄酚含量的电化学分析新方法。方法:采用循环伏安法研究大黄酚在玻碳电极上的电化学行为及其电极反应机理,以差示脉冲伏安法建立了检测大黄酚含量的电化学分析新方法。结果:在pH4.0醋酸盐缓冲液中,-0.8～+0.2V点位区间内,大黄酚在玻碳电极表面发生的电极反应是受吸附控制的准可逆双电子转移过程,电子转移系数α=0.604;以差示脉冲伏安法(DPV)测得其氧化峰电流Ipa与浓度在1.0×10-7～9.0×10-6mol·L-1范围内呈良好的线性关系,检出限为5.0×10-8mol·L-1。重现性试验的RSD为2.9%,加样回收率为98%～104%。结论:本法操作简单、快速准确,并用于实际样品中药大黄中大黄酚的含量检测,结果令人满意。
OBJECTIVE: To study the electrochemical behavior of chrysophanol at glassy carbon electrode and establish a new electrochemical method for the determination of chrysophanol content. Methods: The electrochemical behavior of chrysophanol at glassy carbon electrode and its electrode reaction mechanism were studied by cyclic voltammetry. A new electrochemical method for the determination of chrysophanol was established by differential pulse voltammetry. Results: In pH 4.0 acetate buffer, the electrode reaction of chrysophanol on the surface of glassy carbon electrode under the potential of -0.8 ~ + 0.2V is a quasi-reversible two-electron transfer process controlled by adsorption. The electron transfer coefficient α = 0.604. The peak current Ipa measured by differential pulse voltammetry (DPV) showed a good linearity with the concentration range of 1.0 × 10-7 ~ 9.0 × 10-6mol·L-1. The detection limit 5.0 × 10-8mol·L-1. The reproducibility test showed a RSD of 2.9% and a recovery of 98% -104%. Conclusion: This method is simple, rapid and accurate, and is used to detect the content of chrysophanol in Chinese medicinal rhubarb. The result is satisfactory.