A Novel Photoelectrochemical Sensor for Bisphenol A with High Sensitivity and Selectivity Based on Surface Molecularly Imprinted Polypyrrole Modified TiO2 Nanotubes

A novel and simple photoelectrochemical (PEC) sensor is proposed to detect endocrine disruptor bisphenol A (BPA) based on vertically aligned TiO2 nanotubes (TiO2 NTs) with surface molecularly imprinted polypyrrole (PPy) for the first time. The developed PEC analytical method towards BPA successfully overcomes the high oxidation overvoltage required in sole electrochemical (EC) method, which may lead to electrochemical polymerization of BPA and accumulation of intermediate products and then bring the passivation of the electrode. Under a very low potential (50mV vs. SCE), a highly sensitive PEC response for BPA is obtained in the linear range from 4.5 to 108nM with a limit of detection (LOD) as low as 2.0nM. Simultaneously, by combining the surface molecularly imprinted polymer (MIP) technique with PEC method, specific recognition of BPA can be realized on the PEC sensor, even in coexisting systems containing 100-fold concentration of other substances with similar structures or chemical properties, such as hydroquinone, 1-naphthol or triphenylcarbino. The PEC sensor also presents good applicability and high stability in real water samples. The sensitive and selective recognition mechanisms are further discussed.