Evaluation of unmodified commercial gold screen-printed electrodes for cyclic-voltammetric detection of patulin: analytical response and limitations

Patulin (PAT) is a mycotoxin of regulatory concern in apple-based foods. We evaluated label-free gold screen-printed electrodes (Au/SPEs) against carbon and platinum SPEs for PAT electro-reduction in Britton–Robinson buffer. Au/SPE produced a reproducible cathodic response and was selected for subsequent analytical evaluation. Scan-rate studies demonstrated strongly non-ideal behavior, while the pH study showed a pH-dependent irreversible response. These results did not permit assignment of a specific proton–electron stoichiometry or a diffusion-, adsorption-, or mixed-control mechanism. Under pH 4.0, cyclic-voltammetric (CV) calibration was linear from 1–10 ppb with experimentally determined LOD of 0.42 ppb. The approach showed good repeatability and reproducibility, minimal interference from common sugars/acids/ions, and accurate spike recoveries in commercial apple juice and purée without elaborate pretreatment. The concentration-dependent response demonstrates the feasibility of measurement under the investigated conditions; however, the broad cathodic feature and its partial overlap with the background limit the analytical resolution of direct CV. Accordingly, this configuration is presented as a proof-of-concept evaluation rather than a validated field method.