In this study, a magnetic metal-organic frameworks (MOFs) based hybrid substrate was designed and fabricated for SERS detection of enrofloxacin (ENR) in milk. The magnetic MOF (Fe 3 O 4 @UiO-66-NH 2 ) was synthesized by a facile microwave-assisted method, then loaded with popcorn-like Au nanoparticles (NPs) through electrostatic interaction. The as-prepared SERS substrate (Fe 3 O 4 @UiO-66-NH 2 /Au NPs) integrated the abundant hot spots of popcorn-like Au NPs with porous Fe 3 O 4 @UiO-66-NH 2 , which greatly improved its SERS activity and stability. More importantly, benefiting from the fingerprint characteristics of SERS and adsorption performance of Fe 3 O 4 @UiO-66-NH 2 , the SERS substrate exhibited high selectivity and sensitivity in detecting ENR. Under the optimal detection condition, a good linearity (R 2 = 0.996) was obtained with ENR concentration of 1.0 × 10 −9 –1.0 × 10 −6 M in spiked milk, the LOD was as low as 5.26 × 10 −10 M, and the recoveries were in the range of 76.1–86.1 % at three different spiking levels. The whole detection process including sample pretreatment took about 50 min, which indicating that the prepared substrate has great potential in sensitive and real-time detection of ENR in milk.
In this study, a novel magnetic composite, Ag@Fe 3 O 4 /UiO-66-NH 2 (Ag@FUN), was developed by incorporating a porous metal-organic framework (MOF), UiO-66-NH 2 , which offers selective enrichment capabilities and facilitates solar-driven photoreduction of Cr(VI). The surface coverage of silver nanoparticles on Ag@FUN was precisely controlled by adjusting the AgNO 3 feed concentration, enabling tunable SERS sensitivity. SERS measurements revealed that the Ag@FUN composites exhibited strong signal intensity for Cr(VI), along with excellent signal reproducibility and storage stability. These composites were capable of detecting Cr(VI) at concentrations of as low as 7.81 × 10 -8 M in tap water and 8.89 × 10 -8 M in pond water. The remarkable SERS performance is attributed to the porous MOF structure, which enriches Cr(VI) via Zr–O coordination, electrostatic interactions, and pore-filling effects. Importantly, under simulated sunlight, Ag@FUN effectively reduced Cr(VI) within 70 minutes. The composites also demonstrated outstanding recyclability, retaining their SERS sensitivity and photocatalytic efficiency through five consecutive "detection–reduction" cycles. Overall, the Ag@FUN composites developed in this work exhibit high SERS sensitivity and robust photocatalytic activity, offering significant potential for environmental monitoring and ecological remediation.
危险品化学品经营许可证（带存储）