Ratiometric Fluorescent Sensor Based on Hydrogen-Bond Triggering the Internal Filter Effect for Enzyme-Free and Visual Monitoring Pesticide Residues

This work has imposed great improvementin ratiometric sensingfor pesticide residues and provides a more reliable guarantee forgreen environment sustainability and food safety applications. Real-time/field sensing techniques to keep track of methylparathion(MP) are crucial to human health. In this work, a ratiometric fluorescenceprobe was constructed by integrating green carbon dots and CdTe quantumdots (CdTe QDs) for highly selective quantitative detection of MP.Under alkaline conditions, MP can be rapidly hydrolyzed to producep-nitrophenol (p-NP); the instantaneous reaction that strengthensthe hydrogen bond results in the internal filter effect between thecarbon dots and p-NP, which quenches green fluorescence, thus leadingto an obvious and immediate change from green to red. The probe displayeda sensitive limit of detection of 8.9 nM and exhibited a significantlinear response to MP residue concentrations in the range of 0-100M. In addition, we have created a brand-new smartphone-based intelligentdetection tool by measuring the RGB value of the fluorescent probesolution and the matching paper-based sensor, and we are able to visuallyand quantitatively identify the levels of MP residues present in water,apples, and vegetables. This ratiometric fluorescence sensing methodcan realize rapid visual and quantitative detection of MP residues,which provides a more reliable guarantee promising strategy for constructinga risk detection technique for traces without enzymes.

Automated summary

This study developed a ratiometric fluorescence probe for the highly selective quantitative detection of methylparathion residues. The probe showed a sensitive limit of detection and a linear response to residue concentrations. Additionally, a smartphone-based portable detection tool was created for visual and quantitative detection of methylparathion residues.