Simultaneous detection of dopamine and uric acid under coexistence of ascorbic acid with DNA/Pt nanocluster modified electrode

A novel biosensor by electrochemically codeposited Pt nanoclusters and DNA film was constructed and applied to detection of dopamine (DA) and uric acid (UA) in the presence of high concentration ascorbic acid (AA). Scanning electron microscopy and X-ray photoelectron spectroscopy were used for characterization. This electrode was successfully used to resolve the overlapping voltammetric response of DA, UA and AA into three well-defined peaks with a large anodic peak difference (Delta E-pa) of about 184 mV for DA and 324 mV for UA. The catalytic peak current obtained from differential pulse voltammetry was linearly dependent on the DA concentration from 1.1x10(-7) to 3.8x10(-5) mol.L-1 with a detection limit of 3.6x10(-8) mol.L-1 (S/N=3) and on the UA concentration from 3.0x10(-7) to 5.7x10(-5) mol.L-1 with a detection limit of 1.0x 10(-7) mol.L-1 with coexistence of 1.0x10(-3) mol. L-1 AA. The modified electrode shows good sensitivity and selectivity.