Plasmonic silver nanorod-reinforced flexible polyvinyl alcohol hydrogel SERS sensors for ultrasensitive detection of food colorants in fruit juice.

Excessive consumption of artificial food colorants can lead to potential health risks. There is an urgent need for a rapid and convenient method to detect residues of these artificial colorants. In this research, we developed a flexible AgNRs@PVA surface-enhanced Raman scattering (SERS) sensor by uniformly depositing silver nanorods (AgNRs) onto the surface of a polyvinyl alcohol (PVA) hydrogel. Due to the three-dimensional high-density and uniform hot spots formed by the interwoven one-dimensional silver nanorods, the AgNRs@PVA hydrogel SERS substrate demonstrates outstanding detection sensitivity of 10-11 M, good signal uniformity and exceptional storage stability for malachite green. In addition, the AgNRs@PVA hydrogel SERS substrate exhibits prominent detection sensitivity, achieving limits of 10-7 M and 10-6 M for the artificial food colorants of sunset yellow and carmine in fruit juice. Moreover, AgNRs@PVA SERS substrate also demonstrates satisfactory detection performance and practicality for analysis of artificial food colorants in commercial products.