A sensitive photoelectrochemical aptasensor based on Bi/Bi2MoO6-modified phosphorus-doped ultrathin g-C3N4 formed Z-scheme heterojunction for tetracycline detection.

Tetracycline (TC) is a common antibiotic with broad antibacterial activity, yet its excessive abuse will leave antibiotic residues in animal-derived food, posing some threats to human health. Therefore, developing a simple and effective technology for TC trace analysis is immediately important for food safety. Herein, the sensitive PEC aptasensor within Z-scheme heterojunction, based on Bi/Bi2MoO6 and P-doped ultrathin porous g-C3N4 (PCN), was constructed by elemental doping strategy, hydrothermal method and surface plasmon resonance (SPR) effect. Benefiting from the Z-scheme electron transmission way, the Bi/Bi2MoO6@PCN heterojunction significantly improves both visible-light absorption and the mobility of photogenerated carriers. Thus, the fabricated PEC aptasensor based on Bi/Bi2MoO6@PCN heterojunction exhibited outstanding selectivity and stability for TC detection, which displayed a wider linear range of 0.05-350 nM and a lower detection limit of 0.036 nM. In addition, the proposed aptasensor showed the acceptable recoveries (98.41-104.76 %) for TC residue analysis in animal-derived food, including milk, honey and pork. Therefore, it demonstrates that the PEC sensing technology possesses the excellent feasibility and application potential in food analysis.