SERS analysis of nanoplastics in Chinese Baijiu with an amide-functionalized silver nanowire membrane featuring synergistic interception and adsorption.

The analysis of nanoplastics in Chinese Baijiu is critical given potential consumer exposure and food safety concerns. Herein, an integrated strategy was developed combining membrane filtration with surface-enhanced Raman spectroscopy (SERS), using amide-functionalized silver nanowires (Amide-Ag NWs) membrane as both a filter and a plasmonic substrate. Amide modification introduced synergistic interception and adsorption effects, significantly enhancing capture efficiency for small-sized nanoplastics. The Amide-Ag NWs membrane achieved >95% retention for 100-500 nm polystyrene (PS) and 78% for 50 nm PS, a 4.3-fold improvement over unmodified membranes. This method enabled direct capture and SERS detection without pre-aggregation, preserving original particle sizes, and yielded a cleaner SERS background with a detection limit of 1 × 10-5 g·L-1 for 50 nm PS. Its applicability was demonstrated in Baijiu matrix and simulated PS-release samples.