Construction of a modified carbon paste electrode based on TiO2 nanoparticles for the determination of gallic acid

A modified carbon paste electrode was prepared by incorporating the TiO2 nanoparticles in the carbon paste matrix. The electrochemical behavior of gallic acid (GA) is investigated on the surface of the electrode using cyclic voltammetry and differential pulse voltammetry. The surface morphology of the prepared electrode was characterized using the scanning electron microscopy. The results indicate that the electrochemical response of GA is improved significantly at the modified electrode compared with the unmodified electrode. Furthermore, the capabilities of electron transfer on these two electrodes were also investigated by electrochemical impedance spectroscopy. Under the optimized condition, a linear dynamic range of 2.5 x 10(-6) to 1.5 x 10(-4) mol L-1 with detection limit of 9.4 x 10(-7) mol L-1 for GA is obtained in buffered solutions with pH 1.7. Finally, the proposed modified electrode was successfully used in real sample analysis.