Preparation of TiO₂ Nanoparticles/2,2'-(1,3-propanediylbisnitrilo-ethylidine)bis-Hydroquinone Carbon Paste Electrode and Its Application for Simultaneous Sensing of Trace Amounts of Ascorbic acid, Uric acid and Folic acid

摘要

A carbon paste electrode modified with 2,2(1,3-propanediylbisnitrilo-ethylidine)bis-hydroquinone(PBNBH) and TiO2 nanoparticles was prepared. The modified carbon paste electrode exhibitsexcellent electrocatalytic activity towards the oxidation of ascorbic acid (AA), uric acid (UA) and folicacid (FA) and reduced the overpotential for AA oxidation to about 380 mV lower than that of the bareelectrode. The modified carbon paste electrode could separate the anodic peaks of AA, UA and FA in amixture. Potential differences of 330 mV (AA/UA) and 560 mV (AA/FA) were observed, which werelarge enough to allow for the determination of AA, UA and FA. The catalytic peak current obtainedfrom differential pulse voltammetry (DPV was linearly dependent on the AA concentration in therange of 4.0-600.0 M. The detection limit (2) for AA was 0.4 M with a sensitivity of 0.785 A-1 M and a correlation coefficient of 0.9998. The electron transfer rate constant, ks, and charge transfer coefficient, , were calculated to be 1.55 s and 0.34, respectively.