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能彼此分离(ΔEpDA,AA=170 mV, ΔEpDA,UA=130 mV, ΔEpAA,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2.0×10-6~1.5×10-3 mol?L-1, 6.0×10-7~1.0×10-3 mol?L-1, 6.0×10-7~1.0×10-3 mol?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中DA、VC片剂中AA及人尿液中UA的测定．

The citric acid modified glassy carbon electrode (CA/GC) was constructed by potentiostatic technique and used for simultaneous determinations 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 determinations of AA, DA and UA.