Direct electrochemical sensing coupled with in-depth theoretical analysis for the universal detection of organophosphorus pesticides.

More recently, electrochemical sensors developed for the universal detection of organophosphorus pesticide (OPs) usually rely on the bioenzyme-inhibition principle and intricate catalytic cascade reactions. In this work, we developed an efficient direct electrochemical sensor of OPs by using carbon nanotubes coated with NH2-UiO-66 MOF (CNTs@NH2-UiO-66) as multifunctional electrode material, which could effectively eliminate the need for bioenzymes and cascade reactions to achieve universal detection. In this proposal, the NH2-UiO-66 MOF exhibits intrinsic electroactivity as signal probe and specific coordination capability toward OPs structures, while CNTs could endow the nanomaterial with superior conductivity. Using paraoxon as a model analyte, the CNTs@NH₂-UiO-66 sensor exhibits a broad linear detection range (0.01-100 ng/mL), an ultra-low detection limit of 2.71 pg/mL. Furthermore, the sensing mechanism is systematically validated through multiple experimental techniques, complemented by in-depth theoretical analysis. This innovative direct electrochemical sensing strategy holds significant promise for practical OPs analysis in diverse fields.