Novel Clean-Background Coffee Ring SERS Platform for Trace Toxin Analysis

O@AgCl coffee rings. By fine-tuning surface ligands and laser wavelength, a clean SERS background was obtained for the accurate detection of biotoxins. The CC-SERS platform exhibited a strong linear response for STX, neo-STX and microcystins (MC-LR and MC-RR) with limit of detection (LOD, 3δ/k) of 3.3, 1.3, 2.2 and 2.2 nM, respectively. By employing principal component analysis (PCA), we effectively differentiated between highly similar biotoxins, ensuring precise identification within complex samples. The accuracy and sensitivity of this detection platform were validated through high-performance liquid chromatography (HPLC) and high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of real samples, indicating its promising application in ensuring food safety.