Preconcentration of tetracycline antibiotic using cerium oxide nanoparticles and determination by HPLC

Tetracyclines (TCs) constitute a group of antibiotics, which are naturally obtained by fermentation with some fungi or by semi-synthetic processes, characterized by a broad spectrum ofactivity against pathogenic microorganisms, acting by inhibiting the formation of proteins within bacteria [1]. Therefore, determination of trace TC residues is important. In this research work a simple with an extraction column containing cerium oxide nanoparticles (CeO2) as adsorbent for preconcentration of tetracycline antibiotic and determination by HPLC. In this study the effects of parameters such as pH‚ buffer and its volume‚ composition and volume of desorbing solvent, ionic strength‚ accepted tolerable volume‚ amount of adsorbent and evidence of some co-existing ions on the preconcentration of tetracycline were investigated. In optimum condition the linear dynamic ranges for the determination of TC in aqueous solutions was 0.01 to 5 mg L-1 with correlation coefficient (r) 0.9991, the ilimit of detection (LOD) and relative standard deviation (RSD) for 1 mg L-1 and 5 mg L-1 of TC were 0.004 mg L-1 and less than 2.613 % and 1.044 % (n= 7), respectivilly. The experimental recovery results for the determination of TC in pharmaceutical and plasma serum of human blood samples was 101.8 % and 95.6%, respectively. Results of examining the effect of various parameters on preconcentration of TC, illustrated that this proposed method is effectively efficient for preconcentration and determination of low concentration of TC. The proposed method has the advantages that the column which are used as bed for cerium oxide nanoparticles may reused for further preconcentration processes and amount of adsorbent used for an analysis is low (5 mg of cerium oxide nanoparticles). The proposed procedure is clean, offers high preconcentration factors and also had better or comparable LOD and RSD, and recovery values with a variety of other methods reported in the literature for the determination of some related compounds.