Selective thin film microextraction of naproxen from biological and environmental matrices utilizing chitosan-derived bio-imprinted polymer with fluorescence detection

Abstract

This study presents the selective isolation of naproxen (NAP) from complex matrices through the synthesis of a self-supporting chitosan-derived molecularly imprinted polymer (MIP) monolithic thin film as a tailor-made adsorbent for selective thin film microextraction (TFME), followed by quantification utilizing fluorescence spectroscopy. The chitosan-MIP thin film was characterized through field-emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR) spectroscopy. Key parameters affecting the extraction efficiency, including the film size, desorption solvent, extraction time, desorption time, salt concentration, and pH, were optimized by employing a one-variable-at-a-time methodology. Under optimized conditions, the method exhibited linear ranges of 6–70 ng mL⁻¹ and 70–1000 ng mL⁻¹ in deionized water, 20–250 ng mL⁻¹ in wastewater and urine samples, and 10–250 ng mL⁻¹ in saliva. The limits of detection (LOD, 3.3 S/N) were 2.0, 6.8, 6.6, and 3.4 ng mL⁻¹ for deionized water, wastewater, urine, and saliva, respectively, while the limits of quantification (LOQ, 10 S/N) ranged from 6.2 to 20.0 ng mL⁻¹ for various matrices. Method validation demonstrated excellent precision, with inter-day, intra-day, and inter-film relative standard deviations (RSD%) below 8.0%. High relative recoveries (97.5%–108.2%) in complex biological and environmental samples confirmed the method's accuracy and efficacy for NAP assessment in real samples.