Simultaneous Determination of Theophylline and Uric Acid on Cadmium Sulfide Nanoparticles/Phosphotungstic Acid/Nafion Modified Glassy Carbon Electrode

摘要

In this study, a sensor for the simultaneous determination of uric acid (UA) and theophylline (TP) has been reported for the first time. The sensor was simply constructed by modifying glassy carbon electrode (GCE) with cadmium sulfide nanoparticles (CdS NPs), phosphotungstic acid (PTA) and Nafion. Electrochemical behavior of the modified electrode was evaluated by cyclic voltammetry (CV) technique. The modified electrode (CdS/PTA/Nafion/GCE) shows excellent electrocatalytic capability by substantially reducing the oxidation potential of TP. CdS/PTA/Nafion/GCE also exhibits extraordinary stability by effectively preventing the aggregation of the oxidation product of TP on the electrode surface. The differential pulse voltammetric (DPV) results indicated that there was good linear relationship between anodic peak currents and the concentrations of TP and UA in the range from 1 × 10~(-6) to 2 × 10~(-4) M and 5 × 10~(-6) to 1 × 10~(-3) M with the detection limit of 6 × 10~(-7) M and 2 × 10~(-6) M (S/N = 3), respectively. Furthermore, the applicability of the sensor for TP and UA analysis in urine has been successfully demonstrated.