Determination of chloramphenicol and tetracycline residues in milk samples by means of nanofiber coated magnetic particles prior to high-performance liquid chromatography-diode array detection

A magnetic solid phase extraction (MSPE) coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD) methodology was developed for the determination of chloramphenicol (CP) and tetracycline (TET) antibiotic residues in milk samples. As a solid phase sorbent, C-nanofiber coated magnetic nanoparticles were synthesized and extensively characterized using Field Emission Scanning Electron Microscopy (FE-SEM), Raman Spectroscopy and X-ray Powder Diffraction (XRD) analysis. Experimental variables of MSPE method for both antibiotic analytes were investigated and optimized systematically. The simultaneous HPLC analysis of CP and TET was performed by using a phenyl-hexyl column under isocratic elution mode by means of a phosphate buffer solution (pH 6.0, 50mM), methanol and acetonitrile (60:10:30) with a flow rate of 1.0 mL min−1. After MSPE, the linear range for both the analytes (r2 > 0.9987) were obtained in a range 20.0–600.0 ng mL−1. The limit of detections (LODs) for CP and TET were 3.02 and 3.52 ng mL-1, respectively while RSDs % were below than 4.0 %. Finally, the developed method based on MPSEHPLC-DAD was applied to real milk samples to quantify the antibiotic residues. Recovery values for each antibiotic compound were found in the range of 94.6–105.4 % (n = 3) by using spiked model solution.