Dual-aptamer intelligent sensing platform based on carbon/niobium carbide nanocomposites for on-site analysis of ochratoxin A and zearalenone

Ochratoxin A (OTA) and zearalenone (ZEN), two ubiquitous mycotoxins accumulating in warm, humid climates, contaminate crops and foods, making accurate on-site detection essential for safeguarding food safety and environmental health. In this study, carbon/niobium carbide nanomaterials (C/NbCNMs) with superior peroxidase-like activity were synthesized through a carbothermal reduction process followed by dilute-acid etching—a treatment that generated abundant active sites and a large specific surface area. Leveraging the nanozyme activity of C/NbCNMs and the specific recognition capability of aptamers, a dual-aptamer colorimetric sensing platform (C/NbCNMs@OTA-Apt and C/NbCNMs@ZEN-Apt) was constructed for the parallel detection of OTA and ZEN. Aptamer conjugation markedly enhanced the catalytic activity of the nanozyme, amplified the chromogenic signal, and enabled detection limits as low as 19 pg mL −1 (0.019 ng mL −1 ) for OTA and 16 pg mL −1 for ZEN, with visual detection limits of 60 and 50 pg mL −1 , respectively. For high-throughput analysis, a dual-channel intelligent model was established to predict toxin concentrations within 10 s via chromatic characteristic analysis. Moreover, the sensing platform exhibited excellent practicality and accuracy in naturally contaminated food samples, with relative standard deviations (RSD) of 3.30 % for OTA and 3.84 % for ZEN. This work offers a low-cost, highly sensitive, portable, and intelligent alternative to conventional mycotoxin detection methods, facilitating rapid on-site screening of OTA, ZEN, and other analogous contaminants.