Fluorescent aptamer sensors based on carbon quantum dots: application of quenching-recovery mechanism in acetamiprid detection

Abstract

Food safety concerns have driven the development of rapid and sensitive methods for pesticide detection. In this study, fluorescent carbon quantum dots (CQDs) were synthesized via a hydrothermal method using azodicarbonamide and citric acid as precursors. The thermal decomposition of azodicarbonamide generated gas, facilitating the formation of smaller, well-dispersed CQDs with an absorption peak at 346 nm and an emission peak at 448 nm. To enhance specificity, a selective aptamer was conjugated to the CQDs under optimized conditions (molar ratio 1 : 3, pH 7.5). Upon binding with acetamiprid, fluorescence recovery enabled quantitative detection, with a quenching mechanism primarily attributed to static quenching. The developed aptamer–CQD sensor exhibited high sensitivity and selectivity, with a detection limit suitable for real-world applications. These findings highlight the potential of aptamer-functionalized CQDs as a robust and reliable platform for pesticide residue analysis, contributing to advancements in food safety monitoring.