Developing an applicable electrochemical micro-sensor for highly specific detecting chlortetracycline in water with o-phenylenediamine-based molecularly imprinted polymer

The excessive use of chlortetracycline (CTC) has the potential to adversely affect ecosystems and threat human health by inducing antibiotic-resistant infections, necessitating a rapid, sensitive and accurate detection method for CTC. Here, an electrochemical sensor based on molecularly imprinted polymer (MIP) has been developed that utilized poly o-phenylenediamine (poly-o-PD) film to specificity detect CTC, which preparation process was low-cost, time-saving and simple. It combines the recognition capabilities of MIP with the outstanding electrochemical performance of electrode modification materials, namely tungsten disulfide (WS 2 ) and carboxylated multi-walled carbon nanotubes (MWCNTs-COOH). And, in order to verified the optimal ratio of CTC (template) and o-PD (monomer), the density functional theory is performed by Vienna Ab Initio Simulation Package (VASP) within the generalized gradient approximation to calculate the interaction energy of CTC-o-PD. The sensor detects CTC by analyzing the current changes of the redox-active probes in response to the binding of CTC to the imprinted sites on the modified electrode surface. The sensor reveals a high affinity toward CTC binding, enabling the detection of CTC concentrations within the range of 0.5 – 425.0 μM, with a detection limit of 18.5 nM (S/N = 3). Meanwhile, the sensor harnesses the advantages of screen-printed electrode (SPE) such as miniaturization, suitability for large-scale production, and cost-effectiveness, to further enhance the practicality. The sensor described herein has been successfully used for specific quantitative detection of CTC in actual water, demonstrating its practical applicability.