Boosted photoelectrochemical sensor for methyl parathion detection in vegetables based on covalent organic...

An ultrasensitive and selective photoelectrochemical (PEC) sensor for methyl parathion (MP) determination was exploited by using Bi₂WO₆ quantum dots (QDs)/Wurster-type covalent organic frameworks (COFs) heterostructure grafted electron donor-acceptor molecularly imprinted polymers (MIPs). Bi₂WO₆ QDs/COF_WOTA composites were used as the photoelectrically active material and MIPs were electrochemically deposited on them with MP and p-aminothiophenol acting as the electron acceptor and donor, respectively. Owing to the boosted charge transfer efficiency and enhanced photoelectric currents by the Bi₂WO₆ QDs/COF_WOTA composites, as well as the high specificity provided by the combination of the donor-acceptor mechanism and molecular imprinted technology, the designed sensor achieved a linear range from 10.0 fmol L^-1 to 1.0 nmol L^-1and an extremely low detection limit of 1.096 fmol L^-1. Moreover, it showed good reliability and practicability in real samples assay. This study expanded the application of PEC sensors in food safety risk monitoring.