甘草苷的电化学伏安行为及其应用

Electrochemical voltampere behaviors of liquiritin and its application

目的:研究了甘草苷(LQ)在碳糊电极(CPE)上的电化学行为及电化学动力学性质,据此建立了LQ的方波伏安法的新测定方法。方法:采用循环伏安法(CV)、控制电位电解库仑法(BE)、计时库仑法(CC)、计时电流法(CA)及方波伏安法(SWV)等电化学方法。结果:LQ在CPE上的电化学过程是一不可逆电化学氧化过程,氧化峰电位(Ep)为0.882 V。在扫描速度10～800 mV.s-1范围内其氧化峰电流与扫描速度平方根(υ1/2)呈良好的线性关系,表明LQ在CPE上的伏安行为是一受扩散控制的电极过程。用SWV法测定LQ的氧化峰电流与其浓度在1.8×10-7～1.6×10-3 mol.L-1(r=0.9964)范围内呈良好的线性关系,检出限8.0×10-8 mol.L-1,RSD 2.8%～3.2%,加样回收率98.0%～102.0%。结论:该方法简便快捷,用于中成药及模拟尿样中LQ含量测定,结果令人满意。

Objective：To study electrochemical voltampere behaviors and its electrochemical kinetic parameters of liquiritin（LQ） at carbon paste electrode（CPE）.Methods：Cyclic voltammetry（CV）,bulk electrolysis with coulometry（BE）,chronocoulometry（CC）,chronoamperometry（CA） and square wave voltammetry（SWV）.Results：Electrochemical behavior of LQ in 0.10 mol·L-1PBS exhibits an irreversible electrochemical oxidation process at CPE,the oxidation peak potential（Ep） was 0.882 V.The plot of oxidation peak currents versus the square roots of the scanning rates in the potential range of 10-800 mV·s-1 showed a straight line,as expected for a diffusion-limited electrochemical process.Electron transfer number n,electron transfer coefficient α,diffusion coefficient D and the apparent electrode reaction rate constant kf were 2,0.54,8.69×10-6 cm2·s-1 and 1.27×10-3 cm·s-1,respectively.The changes of the oxidation peak currents with LQ concentration were examined by SWV.The oxidation peak currents versus LQ concentration have a good linear relationship in the concentration range of 1.8×10-7-1.6×10-3 mol·L-1with the correlation coefficient of 0.9964,and the detection limit of 8.0×10-8 mol·L-1.The relative standard deviation was between 2.8%-3.2% and the recovery was in the range of 98.0%-102.0%.Conclusion：The proposed method is simple,accurate and can be used for the determination of LQ in samples with the satisfied results.