Carrageenan-Reduced Silver Nanoparticles for Direct and Rapid SERS Detection of Sorbic Acid

This study presents a method for the preparation of a nanoscale silver substrate, which is characterized by good stability and high surface-enhanced Raman scattering (SERS) activity. The substrate is produced using carrageenan as a reducing agent and functionalized materials under heating conditions. The substrate is employed for direct detection of sorbic acid. The substrate’s ability to adsorb sorbic acid molecules is enhanced through CH-π interactions and intermolecular hydrogen bonds, leading to a pronounced SERS effect at 1642 cm⁻¹. Under the selected conditions, the SERS intensity at 1642 cm⁻¹ demonstrated a linear relationship with the concentration of sorbic acid within the range of 5–50 mg/L, with a detection limit of 0.5351 mg/L. Furthermore, this SERS method has been utilized for the quantitative analysis of sorbic acid in actual tea beverage samples, with a detection limit of 2.78 mg/L. It complies with Chinese national standards and offers the advantages of green synthesis, simplicity in operation, and direct detectio

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