Flexible electrochemical sensor with 2D-on-2D layered structure for real-time on-site intelligent detection of carbendazim residues on fresh tea leaves.

• The PLL/WS2/LIG electrode with 2D-on-2D layered structure exhibits an excellent electrochemical property towards CBZ. • The flexible electrochemical sensor, encapsulated by 3D printing, achieve the non-destructive in-situ detection of CBZ on tea leaves. • Easy-to-use visual online cloud platform is developed for convenient and intelligent detection. • Real-time intelligent analysis is realized to monitor the change in CBZ residues to guarantee food safety. Excessive use of carbendazim (CBZ) for controlling fungal disease may result in pesticide residues in growth environments. There is an urgent requirement for real-time detection of CBZ content to enable rapid assessment of pesticide residues. Herein, a novel electrochemical sensor was created, which utilizes a laser-induced graphene (LIG) electrode modified with two-dimensional (2D) tungsten disulfide (WS 2) nanosheets and a poly(L-lysine) (PLL) film to construct a 2D-on-2D layered structure. The PLL/WS 2 /LIG electrode exhibits strong charge transfer, excellent electrocatalytic performance, and high CBZ adsorption capacity, thus leading to enhanced sensitivity. As a result, the sensor exhibits a low detection limit of 1.2 ng/mL (6.2 nM), high sensitivity up to 135.1 μA(μg/mL)−1cm−2, and a wide response range of 0.01 to 1.5 μg/mL. Moreover, an intelligent analysis system, consisting of a portable device that connects to an online cloud platform equipped with a machine learning model and visualization software, has been developed for the real-time detection of CBZ residues on tea leaves in tea plantations. This study demonstrates that the PLL/WS 2 /LIG sensor and the intelligent analysis system have great potential to monitor pesticide residues to guarantee food safety. [Display omitted] [ABSTRACT FROM AUTHOR]