A smartphone-assisted fluorescent sensor using Eu/Tb-MOF nanorods for ultrasensitive and visual monitoring of carbendazim in food samples

Foodborne residue of carbendazim (CBZ) poses a major threat to human health. Here, we rationally designed a smartphone-assisted fluorescent sensor based on bimetallic-organic framework (Eu/Tb-MOF) for ultrasensitive and visual monitoring of CBZ. The Eu/Tb-MOF nanorods fabricated using Eu³⁺/Tb³⁺ as metal nodes and homobenzoic tricarboxylic acid (H₃BTC) as organic ligand exhibit superior optical properties. After adding CBZ, the strong orange fluorescence of Eu/Tb-MOF nanorods was suppressed by the inner filter effect (IFE). The linear ranges of the fluorescent sensor were 0.02–15 and 15–80 µg/mL, with a detection limit as low as 7.09 ng/mL. The analyses of CBZ residue in tomato and orange samples showed satisfactory recoveries of 98.93 %–101.97 % and low relative standard deviations of 0.87 %–3.44 %, verifying the practicality of the probe for CBZ. Notably, a simple and portable smartphone-assisted sensing platform based on the Eu/Tb-MOF nanorods was successfully constructed for quick, visual, and real-time monitoring of CBZ residue. This work provides an efficient onsite analytical method for assessment and warning-early of CBZ to safeguard food quality.