A two-dimensional nanomaterial-based substrate for the simultaneous SERS detection of three antibiotic substances

A SERS substrate composed of gold nanoparticles anchored on ro-oxidized graphene oxide via a 4-aminothiophenol (4-ATP) linker (Au/4-ATP-ro-GO) was synthesized. The strong interactions between the thiol groups of 4-ATP and AuNPs improve the loading density of plasmonic AuNPs on GO surface. Moreover, the findings demonstrated that the adsorption of analytes onto the AuNP surface was driven by interactions between the negatively charged oxygen-containing functional groups in the target molecules and the positively charged carbon atoms present on the surface of GO, leading to an improvement in SERS sensing sensitivity. When combined with the optimized pretreatment protocol, the resulting hybrid substrate enables the simultaneous detection of three residual antibiotics-nitrofurantoin, tetracycline, and sulfadiazine-in milk samples within 10 min, achieving a detection limit as low as 8.6-15.3 ng g^-1. Compared to national standard methods, the established SERS method enhances analytical efficiency while maintaining detection performance, demonstrating substantial potential for practical application.