Ag@MIL-101(Cr) Film Substrate with High SERS Enhancement Effect and Uniformity

Surface-enhanced Raman scattering (SERS), owing to its high sensitivity and rapid response, has been widely used in various fields. However, it is still a challenge to prepare SERS substrates with high stability and reproducibility. Metal–organic frameworks (MOFs), with excellent enrichment capacity and stability, provide a new material for high-performance SERS substrates. In this paper, we prepare a MIL-101(Cr) film via a secondary growth method, and Ag+ is reduced to Ag NPs by UV irradiation and attach to the film to synthesize the Ag@MIL-101(Cr) film SERS substrate. Then, we change the time of UV light illumination and the amount of silver nitrate in order to obtain the optimal substrate. The detection capability of this sample can be up to 10–11 M for 4-ATP, and the relative standard deviation (RSD) is only about 5%, which demonstrates that the substrate has excellent SERS effect and reproducibility. Finally, the prepared substrate has been applied for the determination of nitrofurantoin, with its detection capability up to 10–7 M. This work proposes a simple method to synthesize MOF-based film substrate with high SERS performance and uniformity and provides potential for the sensitive detection of chemical or antibiotic residue.