A novel ratiometric electrochemical sensor based on bifunctional copper-coordinated polydopamine molecular imprinting for the detection of chlorpromazine

Single-signal based sensors generally suffer from the influence of operation condition fluctuation and environmental change, resulting in reduced accuracy. Herein a novel ratiometric electrochemical sensor based on polydopamine and ZnMn₂O₄/carbon nanotube (ZMO/MWCNTs) for the detection of antipsychotic drug chlorpromazine (CPZ) was presented. The ZMO/MWCNTs composite was employed as substrate for electrode modification, which not only facilitated electron transfer but also provided a large surface for loading molecularly imprinted polymer (MIP). Dopamine coordinated with copper ions served as the monomer, and the MIP film was prepared on the electrode surface through electropolymerization. While acting as a molecularly imprinted polymer, the polydopamine also functioned as an internal reference probe to correct the influence of condition fluctuations and enhance measurement reliability. Furthermore, the introduction of copper ions improved imprinting efficiency and reduced charge transfer resistance. Under optimized conditions, the developed Cu-MIP/ZMO/MWCNTs/GCE sensor enabled CPZ quantification over a wide linear range (1 nM-10 μM) with a detection limit of 0.42   nM. Recovery tests in human serum and lake water samples showed satisfactory results (85.0%−116.0%), with no significant difference compared to the results obtained using high-performance liquid chromatography.