Construction of Reusable PMMA–Ag/g-C3N4/Ag Hybrid Substrates with Plasmonic-Enhanced Intrinsic Raman Signals for Quantitative SERS Detection and Green Degradation

Pesticides and additives, extensively used in the raw agriculture samples and processed food, have attracted tremendous interests owing to their latent menace to the surroundings and human health. Herein, a rationally designed multifunctional polymethyl methacrylate-silver/graphite-like carbon nitride/silver (PMMA–Ag/g-C3N4/Ag) hybrid substrate with plasmonic-enhanced intrinsic Raman signals was exploited and served as a recyclable and quantitative surface-enhanced Raman scattering (SERS) sensor. Especially, the as-prepared flexible substrate with an electromagnetic enhancement factor of 1.64 × 106 could realize the sensitive monitoring and in-situ degradation of thiabendazole (TBZ) and carmine acid (CA) on apple or in applesauce with limits of detection as low as 2.29 × 10–6 and 6.76 × 10–5 mg/mL. Furthermore, heightened linear correlations with coefficients of 0.996 and 0.997 were accurately acquired using the film peak of PMMA as an internal standard. It was proved that the proposed sophisticated substrate may present attractive superior-in-practice multiplexed quantitative monitoring and facile decomposing of harmful molecules. The resulting recovery values distributed from 60.9 to 126% for the deeply processed foods that were decorated by 10–4 to 1 mg/mL CA together with TBZ.