Graphene oxide doped polyacrylonitrile-co-maleic acid nanofibers for high-performance liquid chromatography determination of amoxicillin and Oxytetracycline in milk.

Detecting and quantifying trace amounts of antibiotics like amoxicillin and oxytetracycline in milk and environmental water samples is crucial for public health and environmental monitoring. This research focuses on developing a novel sorbent for solid-phase extraction (SPE) of amoxicillin and oxytetracycline from milk and environmental water samples, using electrospun graphene oxide-doped poly(acrylonitrile-co-maleic acid) nanocomposite fibers, followed by high-performance liquid chromatography with diode array detection (HPLC-DAD). The fibers were successfully fabricated and characterized using a suite of techniques: SEM-EDX, FTIR, XRD, BET, XPS, TGA, and Raman spectroscopy. The extraction process was optimized by carefully adjusting parameters like desorption solvent (0.60 mL of 0.2 M HCl in methanol), extraction time (60 min), and sample pH (3) to achieve efficient and reliable extraction. Under optimal conditions, the developed method demonstrated good linearity (5-100 µg/L, R² > 0.9925), low detection and quantification limits (1.50 µg/L and 5.0 µg/L for amoxicillin and 1.46 µg/L and 4.8 µg/L for oxytetracycline) and high enrichment factor (21 for amoxicillin and 47 for oxytetracycline). The achievable accuracy and precision of the developed sorbent were satisfying, for incidence, relative recovery range of 90.3-106.3% and 87.6-95.9% with RSD range of 1.9-4.3% and 1.1-4.7% for amoxicillin and oxytetracycline, respectively. The method demonstrates reliable and efficient extraction and quantification of antibiotics from two different classes at maximum residue levels, making it suitable for monitoring antibiotic contamination in food and environmental samples, ultimately promoting better public health outcomes.