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

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-0．16V和-0．22V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ips与DA浓度在1．2×10^-7-3．6×10^-5mol／L范围内呈良好的线性关系，线性回归方程ips（μA）=5．307c（μmol／L）＋0．7891，r=0．9923，检出限为6．0×10^-8mol／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。

Determination of dopamine by polythionine and magnetic-core/porous-shell CoFe2O4/SiO2 composite nanoparticles modified electrode

A polythionine-CoFe2O4/SiO2 composite nanoparticles(PTh-CoFe2O4/SiO2) modified electrode was prepared,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 determination of DA.Satisfactory results are achieved when detecting DA in injections.