A portable electrochemical detection system for rapid quantitative carbendazim analysis in agricultural food

Carbendazim is fungicide used in agriculture. Its contamination harms well-being due to its classification as a carcinogenic compound. Codex Alimentarius Commission (CAC) has established regulations for carbendazim use. However, the current analytical methods are hard to implement due to the advanced instruments and operations. Here, we proposed a simple, rapid, and low-cost method consisting of 1) a sensitive screen-printed carbon-50 % AuNP electrode, 2) a working solution of 0.04 M Britton Robinson buffer pH 5.0 with a sample preparation procedure, extracting for 15 min by 10 g of crops with 20 mL of working solution, 3) an in-house portable potentiostat enabling immediate result delivery. This electrochemical sensor directly quantifies the oxidation of carbendazim in differential pulse voltammetry mode, demonstrating efficiency comparable to the commercial compact potentiostat. Our proposed carbendazim assay had a detection range of 0.05 to 5 mg/kg (r² = 0.983), with a limit of detection (LOD) of 0.246 mg/kg. The carbendazim-contaminated fresh fruit models, including tomatoes, grapes, and chilis, demonstrated an excellent correlation between our proposed carbendazim detection method and UPLC-MS/MS analysis (r² = 0.818). Each test costs approximately USD 1.50 and can be stored in a zip-lock plastic bag at room temperature for over seven months. Our proposed device is a step forward in the development of rapid carbendazim tests, making it suitable for field applications in food and agricultural products.