Chemometric-assisted quantitative SERS detection of okadaic acid using paper-based MoS₂ nanoflower-Au nanoparticle substrate

Food safety has become a critical global concern, and monitoring trace levels of marine biotoxins in shellfish remains a significant challenge for effective seafood safety assessment and public health protection. This study proposes a nanostructured chemometric system for the determination of okadaic acid in shellfish extracts. A MoS₂ nanoflower-Au nanoparticle hybrid plasmonic substrate enhanced Raman signals, showing an estimated enhancement factor of 6.72 × 10⁶. Quantitative analysis combined SERS with PLS-based chemometric models across a concentration range of 1.0 × 10^-4 to 1.0 μg/mL. CARS-PLS showed the strongest prediction capability among the models evaluated, yielding Rc = 0.9954, RMSECV = 0.1231, and RPD = 9.56. Validation in spiked shellfish samples produced recoveries between 95.6% and 101.3%, with RSD between 3.5% and 5.6%, indicating acceptable analytical performance under the conditions tested. These findings indicate that the proposed SERS-chemometric strategy has potential as a screening approach for OA in shellfish extracts.