Determination of tetracycline and cefotaxime residues in honey by micro-solid phase extraction based on electrospun nanofibers coupled with HPLC

In the present study, electrospun polyethylene terephthalate nanofibers doped with graphene oxide nanoparticles (GO-PET) was fabricated and used as an effective adsorbent in micro-solid phase extraction (μ-SPE) of tetracycline (TC) and cefotaxime (CF) from honey samples prior to HPLC. The UV-vis spectrophotometer was utilized in the optimization step. The adsorbent was fully characterized using SEM, FT-IR, BET, and BJH methods. The specific surface area and average pore size of the adsorbent were 79.5 m2 g−1 and 4.83 nm, respectively. The honey samples were dissolved in water (5% w/v) at 50 °C for 10 min, centrifuged at 4000 rpm for 15 min and finally filtered using a filter paper before performing the extraction. The important factors of the method were studied to obtain the optimal conditions. Under the optimum conditions (sample solution, 100 mL; adsorbent, 40 mg; pH 5; extraction time, 10 min; desorption solvent; MeOH, 200 μL), the limits of detection for TC and CF were 15.3 and 3.0 μg kg−1. The linear dynamic range (LDR) was obtained as 10-5000 μg kg−1 with the determination coefficients (R2) of 0.9939 and 0.9959, respectively. The real sample extraction recoveries were 89-94% and 95-98% for TC and CF, respectively. The intra-day and inter-day precisions were 5.6 and 4.9% (n = 3) for TC, and 3.6 and 4.5% (n = 9) for CF.