葛根素在碳纳米管糊电极上的阳极伏安行为及其测定

用循环伏安法和控制电位库仑法研究了葛根素在多壁碳纳米管糊电极(MCNT-PE)上的阳极伏安行为及反应机理.在pH为5.72的B-R缓冲液中,葛根素于+0.64 V(vs.SCE)处产生一氧化峰.其电极反应是有吸附特征的不可逆单电子单质子过程.与碳糊电极(CPE)相比,葛根素在MCNT-PE上的峰电位降低,峰电流增加.表明碳纳米管对葛根素的电化学氧化有催化作用.探讨了产生催化作用的原因.拟定了方波吸附溶出伏安法测定葛根素的新方法.线性范围为8.0×10-7～2.0×10-5mol/L,检出限为3.6×10-7mol/L.用本法测定了药物制剂中葛根素的含量,测得值与标示值吻合,回收率在95.1%～104.0%之间.

Anodic voltammetric behavior and content determination of puerarin on multi-wall carbon nano-tubes paste electrode

The anodic voltammetric behavior and the oxidation mechanism of puerarin on a multi-wall carbon nano-tubes paste electrode are studied using cyclic voltammetry and controlled-potential coulometry.In the B-R buffer of pH 5.72,an oxidation peak of puerarin is produced at +0.64 V (vs.SCE).The electrochemical oxidation of puerarin is an irreversible one-electron and one-proton process with adsorption character.The oxidation peak potential of puerarin is lower and the peak current is greater on the MCNT-PE than on the carbon paste electrode (CPE).This is because MCNT-PE has larger effective surface area and better adsorption property than CPE.A new method for the determination of puerarin content using square-wave adsorptive stripping voltammetry is proposed based on the anodic voltammetric behavior of puerarin.The linear region between the oxidation peak current and the concentration of puerarin is from 8.0×10-7 to 2.0×10-5 mol/L,and the detection limit is 4.6×10-7 mol/L.The proposed method is successfully applied to the determination of puerarin content in pharmaceutical preparations.The determined result tallies with the marked value,and recovery rate is 95.1 %～104 % .