Nano-Cu/PSA III modified glassy carbon electrode for simultaneous determination of ascorbic acid, dopamine and uric acid

Cu nanoparticles (nano-Cu)–poly(sulfonazo III) (PSA III) modified glassy carbon electrode (nano-Cu–PSA III/GCE) had been fabricated and successfully used for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The performance of the nano-Cu–PSA III/GCE towards the electrooxidation of AA, DA and UA had been investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The results showed that the modified electrode not only exhibited excellent electrocatalytic activity toward the electrooxidation of AA, DA and UA in a phosphate buffer solution (PBS, pH 4.0), but also could separate the overlapped oxidation waves of these species at the bare GCE into three sharp and strong oxidation peaks at 0.23 V, 0.37 V and 0.54 V using CV and 0.16 V, 0.33 V and 0.49 V using DPV, corresponding to the electrooxidation of AA, DA and UA, respectively. The separations of anodic peak potentials for AA–DA, DA–UA and AA–UA at nano-Cu–PSA III/GCE are large enough for the simultaneous detection of AA, DA and UA. Under the optimum conditions, the linear calibration curves were obtained over the range of 0.30–730, 0.02–65 and 0.25–107 μmol L−1 with detection limits of 0.15, 0.01 and 0.10 μmol L−1 for AA, DA and UA (S/N = 3), respectively. Due to the good selectivity and high sensitivity, nano-Cu–PSA III/GCE had been used for the simultaneous determination of AA and UA in urine samples and DA in human serum samples with satisfactory results.