Core–shell Ag-molecularly imprinted composite for SERS detection of carbendazim
Carbendazim is widely used in agriculture with resultant residues persisting in the environment posing a major concern to human and animal reproductive health. The focus of this study is to develop a stable and highly selective substrate for rapid, sensitive and cost-effective detection of carbendazim residues. A surface-enhanced Raman spectroscopy (SERS) active core–shell substrate was successfully prepared using molecular imprinting technology. Silver nanoparticles were prepared and coated with a thin silica (SiO2) shell to enhance the substrates' stability and recyclability. Subsequently, molecular imprinting on the Ag@SiO2 by precipitation polymerisation using carbendazim as the template was to ensure selectivity of the substrate. The composite Ag@SiO2-molecularly imprinted polymers(MIP) could selectively rebind and successfully detect carbendazim by SERS at concentrations as low as 10−9 M. The intensity of the Raman peaks increased with increase in the concentration of carbendazim. In addition, the substrate demonstrated reasonable reproducibility and reusability. The detection of carbendazim can be attributed to the presence of carbendazim-specific cavities on the imprinted shell to allow the analyte get onto or near the plasmonic core allowing electromagnetic and chemical enhancement resulting in the SERS signal. Therefore, Ag@SiO2-MIP is a stable and selective SERS substrate for detection of carbendazim.