MIL-125(Ti)-derived COOH functionalized TiO2 grafted molecularly imprinted polymers for photoelectrochemical sensing of ofloxacin

Abstract

In this study, a molecularly imprinted polymers-assisted photoelectrochemical (MIPs-PEC) sensor was fabricated for the ultrasensitive detection of ofloxacin based on MIL-125(Ti)-derived COOH functionalized TiO2 grafted MIPs as the PEC signal probe. The COOH functionalized TiO2 (TiO2-C) with excellent conductivity, light absorption capacity and photoelectric conversion rate was obtained through one-step calcination of metal-organic framework (MIL-125(Ti)). It was worth mentioning that the photocurrent response signal of TiO2-C was much larger than that of MIL-125(Ti). Meanwhile, benefiting from the large specific surface area and abundant functional groups of cake-like TiO2-C, the grafting of MIPs as a recognition element becomes more convenient and robust. The MIPs@TiO2-C with a large number of binding sites also had precise electron transfer channels due to the template molecules in the MIPs grafted TiO2-C were removed by photodesorption. Furthermore, this strategy of MIPs modification greatly promoted the selectivity and sensitivity of the established PEC sensor. Under optimal conditions, the MIPs@TiO2-C/ITO PEC sensor had a good linear relationship with the OFL concentration in the range of 0.01–3000 ng mL−1, and the detection limit was calculated as 2.91 ng mL−1 (S/N = 3). Moreover, the prepared MIPs-PEC sensor exhibited excellent stability, interference resistance and practicability in real water samples. This work provided a new vision for the design of photoactive materials in PEC sensors and the monitoring of other pollutants in the environment.