Development of a Photopolymerized Molecularly Imprinted Polymers (MIPs) Coated Surface Plasmon Resonance (SPR) Sensor for the Sensitive Determination of Sulfamethazine in Food Products

This research reports the successful development of a novel optical chemosensor for the determination of sulfamethazine (SMZ) based on a surface plasmon resonance (SPR) transducer coated with a molecularly imprinted polymers (MIPs) thin film, the MIP recognition layer was fabricated directly onto a gold SPR chip via a facile and controlled in-situ photopolymerization process, using SMZ as the template, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. Characterization of the surface via a scanning electron microscope (SEM), an atomic force microscope (AFM), Fourier transform infrared (FT-IR) spectra and contact angle evaluations validated the creation of a homogeneous. The resulting SPR-MIP sensor presented excellent analytical performance, with a broad linear dynamic range from 0.1 to 50 µM and a low limit of detection (LOD) of 0.003 µM for SMZ, the sensor evinced outstanding selectivity, showing a significantly higher response to SMZ compared to structurally similar analogues such as sulfadiazine and sulfamerazine, with a high imprinting factor of 5.75. Furthermore, the sensor evinced excellent reusability and operational stability, retaining over 95% of its initial binding capacity after ten consecutive regeneration cycles, the practical applicability of the sensor was successfully validated by analyzing SMZ in spiked cow's milk samples, achieving excellent recovery rates ranging from 91.7% to 101.5%. The research specifically focuses on a robust and promising platform that combines the high selectivity of MIPs with the immediate sensitivity of SPR, offering possibilities for implementing accurate and cost-effective systems for fast and reliable food safety monitoring.