Mesoporous Au-CuO substrate with dual super-hydrophilicity and efficient chemical enhancement for 4-aminothiophenol SERS detection

aminothiophenol (4-ATP) residues and accumulation in aquaculture/animal husbandry are becoming a serious threat to food safety. Development of highly sensitive metal-semiconductor surface-enhanced Raman scattering (SERS) substrates for the detection of 4-ATP is urgently needed. In this work, mesoporous Au-CuO substrate with dual super-hydrophilicity and efficient chemical enhancement is constructed for high-sensitivity SERS detection of 4-ATP. Mesoporous Au-CuO substrate is prepared by thermal decomposition. The super-hydrophilic substrate could mitigate droplet-induced "coffee ring" effect, thereby promoting rapid diffusion and uniform distribution of target molecules. Meanwhile, hybridizing gold nanoparticles (Au NPs) and CuO could enhance analyte polarization rate in that multi-channel photon-induced charge transfer between the target molecule and Au-CuO substrate. Mesoporous Au-CuO exhibited high sensitivity (10-8 M) and reproducibility (Relative standard deviation (RSD=6.06 %, n=11)) for crystal violet (CV) probe. The as-prepared substrate demonstrated reliable assay ability for 4-ATP with a detection limit of 10-7 M and a good reproducibility with RSD=3.33 % (n=11). Additionally, the substrate was not impacted by heavy metal ions in actual water environment. Trace residues of 4-ATP were still detected at concentrations as low as 10-7 M. Au-CuO substrate is expected to be a favorable candidate for the detection of 4-ATP residues in complex matrices.