Simultaneous SERS detection of illegal food additives rhodamine B and basic orange II based on Au nanorod-incorporated melamine foam

In food safety assessment, surface-enhanced Raman spectroscopy (SERS) is a novel detection method with the advantages of being fast, easy, and of high sensitivity. However, many SERS substrate synthesis methods are complex, and there are only a few studies on the simultaneous detection of multiple substances. In this study, a new, simple, low-cost SERS substrate was synthesised for the first time to simultaneously detect illegal food additives rhodamine B and basic orange II in chilli products. A lightweight, porous, and low-cost material of melamine foam (MF) was employed as the SERS synthesis template. The substrate’s SERS effect on, and sensitivity to, rhodamine B and basic orange II were demonstrated. The molecular vibration and SERS enhancement mechanisms of the two target molecules were analysed by density functional theory (DFT) calculations. The results reveal that this fabricated substrate has great application potential for the supervision and testing industry.