Zearalenone (ZEA) contamination in cereal-based food products represents a significant threat to global food safety and public health. As a potent non-steroidal estrogenic mycotoxin, ZEA mimics 17β-estradiol and acts as an endocrine disruptor, leading to severe reproductive toxicity and pathologies such as hepatotoxicity and immunotoxicity. Its prevalence in staple crops like maize and wheat results in substantial economic losses and necessitates adherence to stringent regulatory limits (e.g., 50 μg/kg set by EFSA) to protect consumers from chronic low-dose exposure. This work reports the development of a novel electrochemical sensor based on a bismuth sulfide nanorod–carbon fiber (Bi2S3-CF) hybrid electrode, fabricated for the first time via a facile, one-pot, in-situ hydrothermal method. This approach was designed to overcome the poor adhesion and high contact resistance associated with conventional drop-casting methods. This fabrication strategy yielded a 3D hierarchical, mesoporous architecture with a specific surface area (SSA) of 120.5 m2/g, as determined by BET analysis, which was 7.9-fold higher than the bare CF substrate. Electrochemical characterization via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated the profound electronic synergy of the hybrid, which exhibited a 35-fold reduction in charge transfer resistance (Rct = 75 Ω) and a 4.4-fold increase in electrochemically active surface area (ECSA) compared to the bare electrode. When applied as a sensor for ZEA using differential pulse voltammetry (DPV), the Bi2S3-CF hybrid electrode displayed outstanding analytical performance, including an ultralow limit of detection (LOD) of 0.003 ng/mL (3 pg/mL) and a wide linear dynamic range from 0.01 ng/mL to 200 ng/mL. The sensor demonstrated high selectivity against other common mycotoxins and was successfully validated in corn flour, wheat flour, and oat flake samples with excellent recovery rates (97.2%–103.4%). This work establishes the Bi2S3-CF hybrid as a robust, low-cost, and highly sensitive platform for practical food safety diagnostics.
Tong et al. (Thu,) studied this question.