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

Abstract

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 exhibits excellent electrocatalytic activity towards the oxidation of ascorbic acid (AA), uric acid (UA) and folic acid (FA) and reduced the overpotential for AA oxidation to about 380 mV lower than that of the bare electrode. The modified carbon paste electrode could separate the anodic peaks of AA, UA and FA in a mixture. Potential differences of 330 mV (AA/UA) and 560 mV (AA/FA) were observed, which were large enough to allow for the determination of AA, UA and FA. The catalytic peak current obtained from differential pulse voltammetry (DPV was linearly dependent on the AA concentration in the range of 4.0-600.0 μM. The detection limit (2σ) for AA was 0.4 μM with a sensitivity of 0.785 μA μM-1 and a correlation coefficient of 0.9998. The electron transfer rate constant, ks, and charge transfer coefficient, α, were calculated to be 1.55 s−1 and 0.34, respectively.