Optical Detection of Azithromycin in Water and Urine Using Molecularly Imprinted Polymer-Microfluidics Integration

Azithromycin (AZM) is one of the most used antibiotics worldwide. Monitoring its concentration in urine and water is essential to control the spread of antibiotic-resistant bacteria. Two new methods for AZM analysis in artificial urine were developed using fluorescence-based microscopic and spectrophotometric techniques after forming an ion-pair complex with fluorescein isothiocyanate. The fluorescence method showed higher sensitivity and precision, with a linear range of 0-31.25 µg/mL, LOD of 0.41 µg/mL, and LOQ of 1.23 µg/mL, compared to the spectrophotometric one. Moreover, it showed a narrower recovery range of AZM from artificial urine samples, indicating higher precision in complex matrices compared to the spectrophotometric one. For enhanced selectivity and portability, a study on integrating molecularly imprinted polymer (MIP) as synthetic receptor inside a microfluidic device with the fluorescence-based detection method was performed. Despite the challenges with specificity, the study constitutes a promising detailed investigation where both extraction and detection of AZM can be done on the same platform using optical techniques. This approach can be potentially extended to enable multiplexing, where a microfluidic device with multiple channels, each containing an MIP specific for a different target compound can be used.