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 nano particles (GO-PET) was fabricated and used as an effective adsorbent in micro-solid phase extraction (mu-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 m(2) g(-1) and 4.83 nm, respectively. The honey samples were dissolved in water (5% w/v) at 50 degrees 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 mu L), the limits of detection for TC and CF were 15.3 and 3.0 mu g kg(-1). The linear dynamic range (LDR) was obtained as 10-5000 mu g kg(-1) with the determination coefficients (R-2) 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.