多巴胺在L-半胱氨酸修饰玻碳电极上的电化学行为及伏安测定

Electrochemical behavior and voltammetric determination of dopamineon L-Cysteine modified glassy carbon electrode

以L-半胱氨酸作为电极修饰剂,采用循环伏安法研究L-Cys/GC电极的制备和DA在该修饰电极的电化学行为及其测定.DA在pH=6.684的磷酸盐缓冲溶液中,在L-Cys/GC电极上产生一对灵敏的氧化还原峰,峰电位分别为Epa=0.180 V和Epc=0.125 V(vs.SCE).同时用伏安法测定DA的线性范围为1×10-3～1.0×10-6 mol/L,检出限可低达1.0×10-7mol/L(S/N=3).对1×10-4 mol/L DA平行测定50次,其相对标准偏差约为2.5%.该电极可望进一步发展为微电极,用于生物活体内的神经递质DA的实际检测.

In this paper,the preparation of L-Cysteine modified glassy carbon electrode is successfully accomplished by cyclic voltammetry with the help of L-Cysteine as a dressing agent.The electrochemical behavior and voltammetric determination of dopamine are studied at the L-Cysteine modified electrode.In pH 6.684 phosphate buffer solution,one pair of oxidation and reduction peaks with E_pa=0.180 V and E_pc=0.125 V（vs.SCE） are obtained.At the same time,the linear range for the determination of dopamine is 1×10-3 ~ 1.0×10-6 mol/L with the detection limit of 1.0×10-7mol/L.The relative standard deviation is 2.5%（n=50,1×10-4 mol/L dopamine）.It shows that the modified electrode is expected to the development of microelectrodes for practical determination of neurotransmitter dopamine in vivo.