An aluminium–organic framework unveiling ultra-sensitive fluorometric detection of pesticide paraoxon-methyl and pharmaceutical drug azathioprine in fruits, vegetables, and wastewater

Abstract

The rapid increase in the concentrations of various harmful, non-biodegradable agrochemicals and pharmaceutical drugs and their metabolites in landfills, and domestic and rural water bodies has become a serious threat to aquatic ecosystems and living beings. Consequently, environmental pollution stemming from the extensive use of agrochemicals and pharmaceuticals has emerged as a pressing concern for modern environmental scientists in past decades. To address this severe environmental pollution and to decontaminate drinking water resources, herein, we have designed a sustainable, eco-friendly, bio-compatible and reusable MOF-based fluorescence sensor for the detection of broadly used organophosphorus pesticide paraoxon-methyl and the pharmaceutical drug azathioprine. This is the first ever reported MOF-based aqueous-phase sensor of both the targeted analytes. Along with extraordinary selectivity, the lowest ever limit of detection (LOD) values of 0.3 nM and 4.2 pM for paraoxon-methyl and azathioprine, respectively, are the special features of this sensor. The shortest ever response time (within 10 s and 5 s for paraoxon-methyl and azathioprine, respectively) has made this probe advantageous as compared to other reported sensors. The equal sensing efficiency of the MOF for sensing paraoxon-methyl in fruits, vegetables and different real water samples, and over a wide range of pH values proves the real-world applicability of this new sensor. The probe was also effective in detecting azathioprine in human blood serum and urine, different water samples from various environments, and different pH media. High selectivity, swift response time, ultra-low level detection ability, versatile applicability, and reusability without loss of significant efficiency make this probe affordable for the sensing of paraoxon-methyl and azathioprine. Moreover, the possible reasons behind the selective sensing of both the analytes by this MOF were thoroughly investigated using appropriate instrumental supports and theoretical simulation.