A recognition-enhanced colorimetric sensor based on molecularly imprinted CoFe LDH nanozymes for detection of enrofloxacin in real water samples

Abstract The widespread occurrence of enrofloxacin (ENR) in aquatic environments poses potential risks to ecosystems and human health. To develop a simple and selective method for ENR detection, a colorimetric sensor was constructed by integrating molecularly imprinted polymers (MIPs) with cobalt iron layered double hydroxides (CoFe LDH). The MIPs@CoFe LDH composite was prepared using chitosan (CS) as the functional monomer and glutaraldehyde (GA) as the crosslinking agent. The imprinted cavities on MIPs@CoFe LDH selectively captured ENR molecules, thereby blocking the diffusion pathway of H 2 O 2 to the active sites of CoFe LDH and inhibiting the generation of reactive oxygen species (ROS). As a result, the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) was suppressed, generating a quantifiable colorimetric response. The proposed sensor exhibited a linear detection range of 0.19–50 µM for ENR with a detection limit of 0.03 µM. The method was further applied to river water samples, achieving recoveries with acceptable relative standard deviations (RSDs). This study provides a molecularly imprinted nanozyme-based approach for the selective detection of ENR in complex aquatic environments.