Doped N/Ag Carbon Dot Catalytic Amplification SERS Strategy for Acetamiprid Coupled Aptamer with 3,3′-Dimethylbiphenyl-4,4′-diamine Oxidizing Reaction

Abstract

The as-prepared co-doped N/Ag carbon dot (CD_NAg) has strong catalysis of H₂O₂ oxidation of 3,3'-dimethylbiphenyl-4,4'-diamine (DBD). It forms an oxidation product (DBD_ox) with surface-enhanced Raman scattering (SERS) activity at 1605 cm^-1 in the silver nanosol substrate, and a CD_NAg catalytic amplification with SERS analytical platform can be structured based on aptamer (Apt) with the DBD oxidizing reaction. For example, the aptamer (Apt) of acetamiprid (ACT) can be adsorbed on the surface of CD_NAg, resulting in inhibited catalytic activity, the reduced generation of DBD_ox, and a weakened SERS intensity. When the target molecule ACT was added, it formed a stable Apt-ACT complex and free CD_NAg that restored catalytic activity and linearly enhanced the SERS signal. Based on this, we proposed a new quantitative SERS analysis method for the determination of 0.01⁻1.5 μg ACT with a detection limit of 0.006 μg/L.