Advancing chloramphenicol detection through a novel porous organic polymer-enhanced screen-printed electrode

This study explores the synthesis and characterization of a novel cationic porous organic polymer (cPOP, referred to as POP1) designed as an active material for electrochemical detection of chloramphenicol (CAP) in complex matrices. Unlike conventional sensing platforms, POP1 provides a high density of accessible adsorption sites and tailored chemical functionality, enabling selective host-guest interactions with CAP and improving sensing performance. The polymer was comprehensively characterized using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), infrared (IR) and Raman spectroscopy and thermogravimetric analysis (TG-DTA). The interaction between POP1 and CAP was investigated by isothermal titration calorimetry (ITC), revealing a spontaneous and enthalpy-driven adsorption process that underpins the sensing response. POP1 was incorporated into a chitosan matrix and deposited onto carbon screen-printed electrodes (C-SPE) to fabricate a robust and reproducible electrochemical sensor for CAP. Under optimized conditions, the sensor exhibited a sensitivity of 48 nA μM^-1, a limit of detection of 1.67 μM, and a limit of quantification of 5 μM, along with good repeatability, selectivity, and operational stability over 30 days. Method validation was carried out using pharmaceutical products (topical suspensions, topical gels, injectable suspension, and eye drops) and animal biological samples (cow milk, cow urine and pig urine) containing CAP, yielding satisfactory analytical performance despite the complexity of the matrices and confirming the applicability of the proposed platform for real-sample analysis. These results demonstrate the potential of POPs as effective electrode modifiers for electrochemical sensors.