聚硫堇和磁性核/壳纳米粒子 CoFe2O4/SiO2修饰电极对多巴胺的测定

摘要

A polythionine-CoFe2O4/SiO2 composite nanoparticles ( PTh- CoFe2O4/SiO2) modified electrode was pre-pared, and the electrochemical behavior of dopamine (DA) on the PTh-CoFe2O4/SiO2 modified electrode has been studied.According to the experiment, the PTh- CoFe2O4/SiO2 modified electrode has stronger electrocatalytic effect on the oxidation of DA than polypyrrole (PTh) modified electrode does. In pH7.5 PBS, one sensitive pair of redox peaks with Epa=-0.16 V, Epc=-0.22 V(vs. SCE) is obtained on the PTh- CoFe2O4/SiO2 modified electrode. The peak current was markedly increased. The oxidation peak current (ipa) increased linearly with the concentrations of DA in the range of 1.2×10-7~3.6×10-5 mol/L. The linear regression equation is ipa(μA)=5.307 c(μmol/L)+0.789 1 with the correlation coefficient of 0.992 3, and the detection limit of 6.0 ×10-8 mol/L. Normal substances didn't affect the de-termination of DA. Satisfactory results are achieved when detecting DA in injections.%　　制备了聚硫堇(PTh)-磁性核/壳纳米粒子 CoFe2O4/SiO2修饰电极.研究了神经递质多巴胺(DA)在该修饰电极上的电化学行为.实验表明, PTh-CoFe2O4/SiO2复合膜修饰电极对 DA 的电催化作用优于 PTh 修饰电极.在 pH7.5的 PBS 中,DA 在该修饰电极上的 CV 曲线于-0.16 V 和-0.22 V 处出现一对灵敏的氧化还原峰,峰电流显著增加.差分脉冲伏安法(DPV)氧化峰电流 ipa 与 DA 浓度在1.2×10-7~3.6×10-5 mol/L 范围内呈良好的线性关系,线性回归方程 ipa(μA)=5.307c(μmol/L)+0.7891, r =0.9923,检出限为6.0×10-8 mol/L (S/N=3).常见物质对 DA 的检测无干扰,DA 注射液样品检测结果与中国药典2010版(二部)规定方法一致