Simultaneous determination of four antibiotics in human urine and hair samples employing a simple and efficient...

Antibiotics containing azithromycin, amoxicillin, doxycycline, tetracycline, and azithromycin are widely utilized in the treatment of bacterial infections, and their determination in biological samples is critical to evaluate their side effects.

A dispersive micro solid-phase extraction (DMSPE) as an efficient sample preparation was developed for the simultaneous extraction of the antibiotics in biological samples. For this purpose, chitosan@Fe₃O₄ nanoparticles were prepared as a green and magnetic sorbent based on a chemical coating of Fe₃O₄ nanoparticles with chitosan.

The sorbent was compared with several sorbents such as ZnO NPs, CuO NPs, and Fe₃O₄ NPs to extract the antibiotics. In addition, effective factors for antibiotic extraction were evaluated and optimized using a central composite design and one factor at a time. The method has wide linearity in the concentration ranges of 2.1-800.0, 3.5-1000.0, 2.0-800.0, and 2.7-1000.0 μg L^-1 with an R-squared higher than 0.9958 for the determination of azithromycin, amoxicillin, doxycycline, and tetracycline, respectively. The limit of detection and limit of quantitation was lower than 1.1 and 3.5 μg L^-1, respectively. The relative standard deviations (RSDs) were also lower than 4.90% for the determination of the analytes at a concentration of 20.0 µg L^-1. High recoveries in the percentage range of 94.70-106.75%, with RSDs between 4.64 and 5.83%, were obtained to analyze spiked urine and hair samples.

The DMSPE-HPLC-DAD procedure displayed various advantages for determining antibiotics, including simple operation, high recoveries, low sample solution and desorption solvent consumption, high preconcentration factors, proper determination time, and simple and inexpensive method of sorbent preparation.