Dual-mode detection of illicit drugs based on ZIF-8/Ag core–shell nanomaterials

In this study, a dual-mode sensing technique based on zeolitic imidazolate framework-8 (ZIF-8) and silver nanoparticle (Ag NP) composites is proposed to achieve visual primary screening and precise confirmation of illicit drugs by integrating the synergistic effect of colorimetric analysis and surface-enhanced Raman scattering (SERS) techniques. Ag NPs were loaded on the surface of ZIF-8 using an <i>in situ</i> synthesis strategy, and nanocomposites with dual enhancements of molecular enrichment and signaling were successfully constructed. The experiments showed that ZIF-8, with its high specific surface area and ordered porous structure, could efficiently adsorb illicit drug molecules. Meanwhile, Ag NPs, acting as a bifunctional active center, enabled the visual primary screening of illicit drugs <i>via</i> chromogenic reactions. Additionally, by utilizing the local surface plasmon resonance (LSPR) effect, Ag NPs formed nanoscale SERS hotspots, enhancing Raman signals for precise trace detection. The method achieves fast and accurate identification of heroin (HER), methamphetamine (MET) and etomidate (ETO). The multimodal sensing array effectively overcomes the limitations of traditional single detection methods in terms of timeliness, sensitivity and field applicability, providing a new idea for multimodal illicit drug detection.