Fluorescence detection of 2, 4-dichlorophenoxyacetic acid by ratiometric fluorescence imaging on paper-based microfluidic chips
Fluorescence detection of pesticide contamination provides timely control of food safety. This study is to construct novel and facile microfluidic paper-based analytical devices for the ratiometric fluorescent determination of pesticides. Through fluorescence resonance energy transfer (FRET) of nitrobenzoxadiazole (NBD) and CdTe quantum dots (QDs), the new microfluidic paper chips allowed the rapid and selective visual detection of 2, 4-dichlorophenoxyacetic acid (2, 4-D). The performance changes of the fluorescent material under the solid matrix material were studied in detail. The sensor products exhibited visual observability and fluorescence characteristics. Under optimized conditions, the sensors showed satisfactory linearity in the range of 0.56-80 μM, and achieved detection limits as low as 90 nM. The sensors were successfully applied for soybean sprouts and lake water samples. The levels of four spiked-in 2, 4-D concentrations were obtained with high recovery rates ranging from 86.2% to 109.5% and the RSD less than 4.19%. Thus, the present work described the integration of surface imprinted graft on cellulose paper and ratiometric fluorescence techniques for highly sensitive separation and detection of pesticide in real food and environmental samples. Ultimately, this study paved an avenue for the development of novel ratiometric fluorescence detection for food safety and environmental issues.