A carbon paste electrode (CPE) modified withferrocene carboxylic acid (FcCA) and TiO2nanoparticles was constructed by incorporating TiO2nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The electrochemical behavior of captopril (CAP) at the surface of the modified electrode was investigated using electroanalytical methods. The modified electrode showed excellent electrocatalytic activity for the oxidation of CAP inaqueous solutions at physiological pH values. Cyclic voltammetric curves showed that the oxidation of CAP at the surface of the modified electrode reduced its overpotential by more than 290 mV. The modified electrode was used for detecting captopril using cyclic voltammetry and square wave voltammetry techniques. A calibration curve in the range of 0.03 to 2400 µmol/L was obtained that had a detection limit of 0.0096 µmol/L (3) under the optimized conditions. The modified electrode was successfully used for the determination of captopril in pharmaceutical and biological samples.
