Rapid aflatoxin detection based on modulated surface plasmon resonance sensor

This is the authors' abstract. We don't add key points for this paper.

A modulated surface plasmon resonance (SPR) sensor based on a 35 nm gold thin film operating at 635 nm in the Kretschmann-Raether configuration is presented for label-free detection and quantitative analysis of aflatoxins B 1 , G 1 , and G 2 . Phase-sensitive detection via lock-in amplification was incorporated to suppress low-frequency noise and improve measurement stability. The sensor exhibits clear and reproducible angular responses, with resonance angle shifts of 1.417°, 0.607°, and 0.303° for AFG1, AFB1, and AFG2, respectively, at 1 ppm, corresponding to instrumental detection limits of 0.06, 0.14, and 0.28 ppm. Time-resolved measurements under green laser irradiation (532 nm) revealed first-order interfacial kinetics (R² ≈ 0.98), demonstrating the platform's capability for dynamic monitoring. Compared with conventional SPR biosensors that rely on antibodies or aptamers, the proposed sensor enables direct discrimination of structurally similar aflatoxin analogues without biorecognition layers, simplifying sensor fabrication while providing rapid, reproducible, and quantitative detection for food safety monitoring.