A dual-mode sensing platform based on metal-organic framework for colorimetric and ratiometric fluorescent detection of organophosphorus pesticide

Abstract

Pesticide residues have raised considerable concern about environmental health and food safety. Despite a great advance in enzymatic sensors for pesticide detection, the intrinsic fragility of native enzyme and possible fake results due to single mode signal have hindered its wide application. Here, a novel dual-mode sensor is reported for organophosphorus pesticide detection by using metal-organic framework (MOF) nanozyme NH₂-CuBDC as sensing element. The intrinsic peroxidase-mimicking activity and fluorescence property of NH₂-CuBDC enable both colorimetric and fluorescent detection of chlorpyrifos. Compared with previously reported chlorpyrifos sensors, our sensor exhibits outstanding sensitivity, and the limits of detection (LOD, S/N = 3) in colorimetric and fluorescent modes are 1.57 ng/mL and 2.33 ng/mL, respectively. No obvious interferences from other substances were measured and chlorpyrifos analysis in real samples presented good reliability, showing practical potential. This work is anticipated to provide new insights to develop multifunctional nanozymes and integrated multi-mode sensing platforms.

Keywords: Bifunctional metal–organic frameworks; Colorimetric sensor; Nanozyme; Organophosphorus pesticides detection; Peroxidase-mimicking activity; Ratiometric fluorescent detection.