尿酸在石墨烯修饰玻碳电极上的电化学行为及测定

以抗坏血酸为还原剂,采用微波水热法化学还原氧化石墨烯合成了石墨烯纳米片,制备了石墨烯修饰的玻碳电极(RGO/GCE),并采用循环伏安法、计时电量法、交流阻抗法等电化学技术研究了尿酸在该修饰电极上的电化学行为及其影响因素。结果表明,在PBS缓冲溶液中,尿酸(UA)在石墨烯修饰电极上的电极反应是一个受扩散控制的不可逆氧化过程。电极反应的转移电子数n=2,有效面积A=0.182 cm2,扩散系数D=1.51×10-6 cm2.s-1。UA的氧化峰电流与其浓度在5.0×10-6～1.5×10-4 mol/L范围内呈良好线性,r=0.995 7。利用该RGO/GCE修饰电极可以快速准确地测定UA,检出限为2.7×10-7 mol/L,加标回收率为98%～100%。

Electrochemical Behavior and Determination of Uric Acid at Reduced Graphene Oxide Modified Electrode

Electrochemical behavior and response of uric acid(UA) was investigated at the chemically reduced graphene oxide(RGO)-modified glassy carbon(GC) electrode(RGO/GC) by cyclic voltammetry,chronocoulometry and AC impedance method.The results showed that,in pH 6.0 PBS buffer solution,the electrochemical oxidation of UA at the RGO/GC modified electrode was irreversible and controlled by diffusion.Some kinetic parameters such as the number(n) of the electron transferred,the effective area(A) of the modified electrode and the diffusion coefficient(D) were calculated to be 2,0.182 cm2 and 1.51×10-6 cm2·s-1,respectively.A good linear relationship between peak current and concentration of UA was observed in the range of 5.0×10-6-1.5×10-4 mol/L,which met the equation of Ip(μA) =6.457+367.5c(mmol/L)(r=0.995 7).The RGO/GCE modified electrode was successfully applied in the determination of UA with a detection limit of 2.7×10-7 mol/L and recoveries of 98%-100%.