Plasmonic metal NP-bismuth composite film with amplified SERS activity for multiple detection of pesticides and veterinary drugs

The abuse and complex formulation of multiple pesticides and veterinary drugs residues caused serious food safety problems, and had potential harm to human health. The establishment of an accurate and sensitive multiple-target sensing method was of paramount significance for the rapid and simultaneous detection of various pesticides and veterinary drugs. In this work, uniform spiky Au@Ag NPs-Bi2WO6 film was designed, and showed enhanced and stable surface-enhanced Raman scattering (SERS) performances. Bi2WO6 doped by oxygen vacancies (OVs) introduced a large number of free carriers for the generation of plasmonic effects. Bi2WO6 as a dielectric medium improved the local electric fields of spiky Au@Ag NPs for SERS enhancement, and the “donor-bridge-acceptor” charge transfer between Bi2WO6 and spiky Au@Ag NPs also strengthened the SERS performances. Spiky Au@Ag NPs-Bi2WO6 film utilized as intense and stable SERS substrate achieved the sensitive quantitative single detection and simultaneous multiplex monitoring of chloramphenicol (CAP), paraquat and malachite green (MG). Spiky Au@Ag NPs-Bi2WO6 structures engineered flexible film was applied for the in-site detection of paraquat on pakchoi and MG on fish. The work provided a new principle for the construction of bismuth assisted plasmonic metal NP film with amplified SERS activity for the multiple detection of various pesticides and veterinary drugs in food.