柠檬酸修饰电极对抗坏血酸、多巴胺和尿酸的同时检测

研究柠檬酸(CA)修饰玻碳电极(CA/GC)在抗坏血酸(AA)、多巴胺(DA)和尿酸(UA)混合体系中的循环伏安(CV)行为.结果表明,AA、DA和UA在CA/GC电极上氧化峰电流增大,且三者氧化峰电位明显分离(ΔEp(DA,AA)=170 mV,ΔEp(DA,UA)=130 mV,ΔEp(AA,UA)=300 mV).据此,可同时检测AA、DA和UA.在优化的实验条件下,AA、DA和UA的氧化峰电流与其浓度分别在2.0×10-6～1.5×10-3mol.L-1,6.0×10-7～1.0×10-3mol.L-1和6.0×10-7～1.0×10-3mol.L-1范围内呈线性关系.该电极重现性好,可用于盐酸多巴胺针剂DA、VC片剂AA及人体尿液UA的测定.

Simultaneous Determination of Ascorbic Acid,Dopamine and Uric Acid at CA/GC Electrode

The citric acid-modified glassy carbon electrode(CA/GC) was constructed by potentiostatic technique and used for simultaneous determination of ascorbic acid(AA),dopamine(DA) and uric acid(UA) by cyclic voltammetry(CV) and differential pulse voltammetry(DPV).The CA/GC electrode exhibits excellent electrocatalytic activity towards AA,DA and UA.The oxidation peaks are well separated with the potential differences between AA and DA,DA and UA,and AA and UA being 170,130 and 300 mV,respectively,which is large enough to determine AA,DA and UA simultaneously.The catalytic peak currents obtained were linearly dependent on the concentrations of AA,DA and UA in the range of 2.0×10-6~1.5×10-3 mol·L-1,6.0×10-7~1.0×10-3 mol·L-1,and 6.0×10-7~1.0×10-3 mol·L-1,respectively.The proposed sensor shows good reproducibility and may be applied practically in the determination of AA,DA and UA in real samples.