Fig. 6. Optimization of the sensor electrochemical parameters. (a) Reproducibility tests executed under identical conditions of concentration, buffer pH, and applied potential. (b) The validity of the 1,2-DAB sensor over 7 days under similar conditions. (c) A comparison of studies of sensors modified with PANI, TiO₂ NPs and PANI-TiO₂ NPs, and (d) the sensor response time.