Abstract: Based on the fluorescence “off-on” principle, a CDs-CZ13/Ti3C2Tx fluorescent aptasensor for the rapid and sensitive detection of carbendazim (CBZ) was developed by taking advantage of the exceptional fluorescence quenching ability of monolayer 2D MXene toward carbon dots (CDs) and its strong adsorption property for CBZ aptamer (CZ13). Under optimal conditions, the sensor exhibited excellent linearity within the concentration range of 0.001–100 μmol/L. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.27 and 0.90 nmol/L, respectively. The recoveries of CBZ in apple juice and tap water samples ranged from 95.00% to 97.70% and from 95.70% to 98.66%, respectively, with relative standard deviation (RSD) less than 5%, ranging from 2.55% to 3.79% and 2.74% to 3.45%, respectively. This sensor demonstrates good selectivity and repeatability, serving as an efficient and precise approach for fluorescence sensing, thus advancing the detection of pesticide residues and expanding the application scope of MXene.

Key words: carbendazim; fluorescent aptamer sensor; carbon dots; MXene; apple juice