研究β,β-二甲基丙烯酰阿卡宁(β,β-dimethyl-acry-lalkannin,简称β,β-DAL)的电化学行为并由差示脉冲伏安法测定其含量.实验表明:β,β-DAL在玻碳电极上具有明显的吸附性,其电极反应是一可逆的双电子双质子过程.在pH4.6的磷酸盐缓冲溶液中,+0.8～-0.4V电位区间内,β,β-DAL的差示脉冲还原峰电流(Ip)与其浓度(C)呈良好的线性关系,浓度范围1.3×10-7～-1.7×10-6mol/L(r=0.9996),检出限4.0×10-8mol/L.本方法灵敏度高、重现性好,用于中药紫草中β,β-DAL的含量测定,结果满意.

The electrochemical behavior of the β,β-dimethyl-acry-lalkannin and a novel differential pulse voltammetric method for the determination of the β,β-DAL content were studied.Experiments indicated that the β,β-DAL has excellent adsorbability and the electrochemical reaction is a reversible two-electro and two-proton process.In phosphate buffer solution(pH 4.6),the differential pulse voltammograms for β,β-DAL reduction signals from +0.8~-0.4 V were monitored.The relationship between reduction peak current and concentration of β,β-DAL is linear in the range of 1.3×10-7~ 1.7×10-6 mol/L(r=0.9996).The detection limit is 4.0×10-8 mol/L.This method is sensitive and reliable for the determination of the β,β-DAL in radix with satisfactory results.