A room temperature synthesized SERS substrate of AgNPs/PVA hydrogel for highly sensitive detection of enrofloxacin using a portable Raman system

Abstract

Enrofloxacin (EnFX), an antibiotic widely used in animal husbandry, can accumulate in the food chain due to excessive or long-term residues, posing a potential threat to human health. Surface-enhanced Raman scattering (SERS) technology, with its advantages of high sensitivity and rapid label-free analysis, offers a new approach for antibiotic residue detection. However, SERS substrate preparation at high temperature, poor signal reproducibility, and dependence on Raman spectroscopy still limit its practical application. To address these issues, this study proposed a flexible SERS substrate preparation scheme based on polyvinyl alcohol (PVA) hydrogel and silver nanoparticles (AgNPs). The substrate is prepared by a room-temperature seed growth method, which is simple, highly reproducible, and can be combined with portable Raman devices for rapid and flexible on-site detection. Research showed that the AgNPs/PVA hydrogel substrate exhibited excellent sensitivity and signal consistency in the detection of enrofloxacin and Rhodamine 6G (R6G), with a relative standard deviation (RSD) as low as 6%, and can be stably stored in air for more than one month. This method combines low cost, high scalability, and excellent environmental adaptability, providing an efficient, economical, and sustainable solution for the portable detection of antibiotic residues.