Photoelectrochemical determination of diclofenac using oriented single-crystalline TiO2 nanoarray modified with molecularly imprinted polypyrrole.

A novel molecular imprint photoelectrochemical (PEC) sensor has been prepared based on oriented single-crystalline TiO2 nanoarray (TNA) material for sensitive detection of diclofenac (DCF). The TNA obtained by the one-step hydrothermal method was characterized by XRD, SEM, and TEM. Polypyrrole film was formed on the TNA by electrochemical method, and DCF was imprinted on the polymer film as the template molecule. After the removal of DCF, there appeared lots of specific recognition sites that matched template molecules. The experimental results demonstrated that the constructed PEC sensor has good sensitivity and selectivity for the detection of DCF, which can be attributed to the high photoelectric conversion efficiency of TNA and the high selectivity of molecular imprinting technology. The fabricated PEC sensor showed a wide detection range (0.05-1000 μM) and a low limit of detection (0.0034 μM) for DCF, as well as good repeatability and stability. The proposed PEC sensor provided an effective strategy in the monitoring of environmental pollutants.