Luminescent metal–organic frameworks for ultrasensitive detection of pesticide and biomarker: In situ imaging and real field application

Frequent uses of pesticides for agricultural led to the environmental pollution and ultimately threaten the human body. On the other hand, the monitoring of the biomarker at the optimum level is also very imperative for human health. So the investigation of smart materials is very essential for visual and on‐site monitoring of pesticide and biomarker. In this regard, we have synthesized highly fluorescent MOF (ZnATA, 1 ) oriented with free‐NH 2 functionality as a guest functional moiety. Framework 1 showed the selective and sensitive ratiometric detection of biomarker riboflavin (RBF). Further, sensor 1 exhibited the discriminating recognition of pesticide 2,6‐dichloro‐4‐nitroaniline (DCNA). The detection limit for both RBF and DCNA is very excellent, and the values are 0.13 and 0.07 ppm, respectively. The detection of RBF and DCNA is very fast (within 3 s) and has been realized through colorimetric response and by cost‐effective paper strip method. Interestingly, the sensor displayed the visual and on‐site (in situ imaging by using real fruit and vegetable) recognition of “DCNA” within 3 s. Sensor 1 further demonstrated the recognition of DCNA in different real field sample (environmental water sample) and RBF in food samples (milk and vitamin B 2 tablet). The mechanism of sensing for DCNA and RBF has been comprehended through the occurrence of photo‐induced electron transfer, forster resonance energy transfer, and inert filter effect. Further, the recognition mechanism is justified by the theoretical study. The presence of free‐NH 2 moiety in the linker of MOF is possibly to establish a strong supramolecular interaction with the analytes.