Bromhexine screening using molecularly imprinted polymers for electrochemiluminescence detection and molecular...

Electrochemiluminescence (ECL) is a highly sensitive detection technique; however, its inherently low selectivity is a significant challenge in analytical and sensing applications. In this study, we developed a system for the specific determination of the pharmaceutical bromhexine (BH). In this system, ECL was combined with a molecularly imprinted polymer (MIP) capable of molecular recognition. A BH-template-based MIP-modified electrode, synthesized by electrolytic polymerization, was prepared. Interestingly, the MIP-modified electrode robustly immobilized the template molecule via peroxidation during electrolytic synthesis. The sensitivity was approximately three times that without further oxidation. X-ray absorption fine structure measurements were performed using synchrotron radiation to characterize interactions between the analyte and the polymer. From the results, a complex mechanism involving hydrogen bonding, π-π interactions, and halogen-π interactions was inferred between the analytical chemical species and the polymer. The fabricated MIP-modified electrode was applied to determine BH in commercially available pharmaceuticals, prescription drugs, and biological urine samples. The results were compared with those from liquid chromatography-mass spectrometry. This system shows potential for development into a selective sensor.