Molecularly imprinted photoelectrochemical sensor for fumonisin B based on GO-CdS heterojunction.

A rapid and ultrasensitive molecularly imprinted photoelectrochemical (MIP-PEC) sensing platform based on ITO electrode modified with GO-CdS heterojunction was prepared for ultrasensitive measure of fumonisin B (FB). CdS quantum dots (QDs) were combined with a suitable amount of graphene oxide (GO) to form a heterojunction to enhance signal response with accurately calculating energy levels (VB/CB or HOMO/LUMO). The MIP-PEC sensor was successful fabricated after MIP was immobilized on the electrode with the basis of these results. In the phosphate buffer solution (PBS), it was clearly observed that the non-elution MIP-PEC sensor had almost no photocurrent response, which was due to the slower electron transfer speed. When the MIP-PEC sensor is eluted in ethanol, its photocurrent response was significantly restored, that was because the fact that the template molecules were washed away, and electron donors entered the holes and accelerated the electron transfer. Its photocurrent response was reduced because of holes blocked when the MIP-PEC sensor was hatched in the template molecules culture fluid. This phenomenon fully showed that the MIP-PEC sensor can specifically detect the target. Thus, The work has a linear range from 0.01 to 1000 ng mL with a detection limit of 4.7 pg mL for FB. Furthermore, the fabricated MIP-PEC sensor will confirm the actual application.