Development of a molecularly imprinted electrochemical sensor based on (Cu-BTC)-MOF and graphene composite for highly sensitive and selective chloramphenicol detection

Abstract

A highly selective molecularly imprinted electrochemical sensor was constructed for chloramphenicol (CAP) detection based on a copper-benzenetricarboxylic acid metal–organic framework (Cu-BTC)-MOF)/graphene (Gr) composite and poly(o-phenylenediamine) (o-PD) molecularly imprinted polymer (MIP). The (Cu-BTC)-MOF exhibits extremely high porosity, adjustable pore size, a large specific surface area, and highly dispersed unsaturated metal sites. These properties enable it to provide active centers, guide the orderly growth of MIPs, or anchor functional groups, all of which are beneficial for improving the detection performance and stability of the sensor. Graphene, as a support substrate for (Cu-BTC)-MOF, can significantly improve the dispersion, structural stability and conductivity of (Cu-BTC)-MOF. o-PD serves as a functional monomer with two amino active sites, which enable hydrogen bonding or electrostatic interactions with the functional groups (such as carboxyl or hydroxyl) of target molecules, thus enhancing template-specific recognition. The aromatic ring of o-PD facilitates π–π stacking and can broaden the recognition scope. The fabricated sensor exhibits a wide detection range of 0.1 to 120 µM, a low detection limit of 0.05 µM and high sensitivity of 0.186 µA µM⁻¹. Furthermore, it also demonstrated good selectivity, reproducibility and high stability. Moreover, the proposed molecularly imprinted electrochemical sensor was successfully used to assess the chloramphenicol content in real food samples. Therefore, this work presents a simple and efficient strategy for detecting chloramphenicol, which could aid in applying molecularly imprinted electrochemical sensors across various detection scenarios.