Flexible photoelectrochemical sensor for highly sensitive chloramphenicol detection based on M-TiO.sub.2-CdTe QDs/CdS QDs composite

Chloramphenicol (CAP) is widely used in the food industry and animal husbandry due to its effective antibiotic effect active against gram-positive and gram-negative microorganisms. However, research shows that it can cause serious adverse reactions and side effects in the human body. In order to effectively monitor the residues of CAP, a novel and simple photoelectrochemical (PEC) sensor for sensitive detection of CAP is fabricated based on M-TiO.sub.2-CdTe QDs/CdS QDs composite. The results show that the prepared M-TiO.sub.2 not only retains the original morphology and structure of MIL-125(Ti), but also exhibits more abundant pore structure and good photoelectrochemical properties. Compared with M-TiO.sub.2, the as-prepared M-TiO.sub.2-CdTe QDs/CdS QDs composite exhibits excellent PEC performances including about ninefold enhancement of photocurrent intensity, which is ascribed to the large surface of M-TiO.sub.2 and the introduction of CdTe QDs and CdS QDs. Based on the selective inhibitory effect of CAP in the photocurrent intensity of the M-TiO.sub.2-CdTe QDs/CdS QDs PEC system, a novel PEC sensor for CAP concentration determination is constructed. The designed PEC sensor demonstrates a linear range from 1 to 140 nmol L.sup.-1 with a detection limit of 0.14 nmol L.sup.-1 (S/N = 3). Moreover, the method is applied to real milk samples to quantify the CAP residues with spiked recoveries in the range of 96.3-106%, and the possible detection mechanism of the M-TiO.sub.2-CdTe QDs/CdS QDs PEC system is also discussed. Graphical abstract