Aptamer-mediated carbon dots as fluorescent signal for ultrasensitive detection of carbendazim in vegetables and fruits

Pesticide residues like carbendazim have always been a great threat to agricultural production and food safety. Herein, a fluorescent aptasensor for carbendazim detection was established based on aptamer-mediated quenching of gold nanoparticles (AuNPs) toward carbon dots (CDs). CZ-13 aptamer can wrap AuNPs and make them dispersed in salt solution, thus quench the fluorescence of CDs. On adding carbendazim, the aptamer is firstly consumed to preferentially combine with pesticides, resulting in the fluorescence recovery of CDs from quenching status. The degree of fluorescence recovery is positively correlated with pesticide concentration, which enables us to establish a fluorescence aptasensor for carbendazim detection. Under optimal conditions, the limit of detection of the fluorescent aptasensor is determined as low as 2.3 μg·L−1. Moreover, the average recovery range of carbendazim in several vegetables and fruits is from 86 % to 99 %, indicating that such aptasensor may have bright application prospects for carbendazim detection in foods.