Lychee-like plasmonic nanocomplex with programmable hierarchical structure: A high-performance SERS platform for monitoring diazepam in aquatic products

In this work, a high-performance lychee-like plasmonic nanocomplex with programmable hierarchical structure (Ag@ZIF-8@Au) was successfully fabricated as surface enhanced Raman scattering (SERS) platform via layer-by-layer assembly for sensitive detection of diazepam (DZP). ZIF-8 has good pre-enrichment for DZP as well as works as a skeleton for preventing aggregation of plasmonic nanoparticles, dramatically boosting sensitivity, stability and reproducibility of the SERS substrate. Furthermore, lychee-like Ag@ZIF-8@Au nanostructures provided numerous SERS “hot spots” for generating the synergistic enhancement effects including lightning rod and resonance coupling effects. By leveraging Ag@ZIF-8@Au substrate, DZP can be exquisitely detected. The detection limit plummets to 0.126 ng mL −1 , while a broad linear detection span of 10 −9 –10 −2 g mL −1 is achieved. Additionally, Ag@ZIF-8@Au can be utilized to identify DZP in aquatic products with a satisfactory recovery rate of 85.3 % to 111.9 %, which indicates its good practical applicability and great potential for monitoring safety of aquatic products.