Quantification of systemic fungicide in stone fruits and nuts based on PVP/CNF-COOH embedded CuCo₂O₄ tertiary...

This work proposes a high-performance electrochemical sensor for sensitive quantification of the systemic fungicide benomyl in stone fruits and nuts. A screen-printed carbon electrode surface was modified with a novel nanocomposite consisting of copper cobalite particles coupled to PVP-functionalized, chemically oxidized carbon nanofibers (CCO/PVP/CNF-COOH/SPE) for surface-controlled electrocatalysis of benomyl. Functionalizing CNF with the surface stabilizer PVP enhanced electrocatalytic activity by increasing hydrophilicity and dispersion. A notable synergistic impact between CCO and PVP/CNF-COOH, along with the precise optimization of electrochemical parameters, allowed quick and accurate benomyl detection. Under optimal conditions, a low detection limit (0.5 nM), high sensitivity (2.43 μAμM^-1 cm^-2), and a broad linear range with benomyl concentrations between 0.04 and 227.22 μM were achieved. Electrochemical outcomes also demonstrated good selectivity, repeatability, stability, and reproducibility. Benomyl was quantified in stone fruits (apricot, peach, cherry) and nuts (pistachio, almond, walnut) with good recoveries (96.67-100.23 %), proving practical feasibility. The proposed electrode is also compatible with portable potentiostats, enabling in-situ measurements and point-of-care applications.