Core-shell structure and twin-cone morphology of Au@Ag@HOF with efficient adsorption capability and high SERS enhancement efficiency for sensitive detection of bisphenol compounds in food

In SERS analysis, SERS substrates often suffer from uneven “hot spot” distribution, poor stability, and susceptibility to oxidation and aggregation, which limit detection precision and accuracy. To overcome these aggregation, this study presents a novel core-shell Au@Ag@hydrogen-bonded organic framework twin cone (Au@Ag@HOF TCs) as efficient SERS substrate. The HOF shell effectively protects Au and Ag from oxidation, thereby enhancing the long-term stability of the SERS substrate. It also prevents signal inhomogeneity caused by noble metal nanoparticle agglomeration and captures target molecules at “hotspots” for maximum Raman enhancement. Leveraging these features, the proposed Au@Ag@HOF TCs enable sensitive detection of bisphenol A, F, and S in food, with detection limits of 1.8033 × 10 −9  M, 4.2170 × 10 −9  M, and 2.0815 × 10 −10  M, respectively. Furthermore, this substrate was successfully applied to analyze real samples, including canned soup, beverages, and milk, demonstrating its potential for the detection of bisphenol compounds in food.