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Dispersive solid-phase microextraction method for sample extraction in the analysis of four tetracyclines in water and milk samples by high-performance liquid chromatography with diode-array detection

Tsai, Wen-Hsien, Huang, Tzou-Chi, Huang, Joh-Jong, Hsue, Yi-Huu, Chuang, Hung-Yi
Journal of chromatography 2009 v.1216 no.12 pp. 2263-2269
milk, food contamination, antibiotic residues, tetracyclines, tetracycline, oxytetracycline, chlortetracycline, doxycycline, solid phase extraction, microextraction, high performance liquid chromatography, milk analysis
A dispersive solid-phase microextraction (dispersive-SPME) method for the determination of tetracycline, oxytetracycline, chlortetracycline and doxycycline is proposed. Different silica-based and polymeric sorbents were evaluated for their capacity to simultaneously preconcentrate tetracyclines (TCs) in the dispersive format from aqueous or organic solutions. Silica-based sorbents especially functionalized with primary amine, secondary amine, or carbonyl groups have showed higher capacity than polymeric sorbents under organic environment. In the proposed dispersive solid-phase microextraction method, after extraction with acetonitrile and salt-promoted partitioning, TCs were adsorbed to a small amount of dispersive silica-based primary and secondary amine sorbents, desorbed with a small volume of desorption solution, and determined by high-performance liquid chromatography with diode-array detection. Under the optimal conditions, recoveries were determined for surface water and milk samples spiked at 10ng/mL and 50-150ng/g, respectively, and quantification was achieved by matrix-matched calibration. The calibration curves of four TCs in both samples showed linearity with a correlation coefficient value above 0.997. Average recoveries ranged from 97.1 to 104.1% and the precision was from 2.0 to 5.6%. Limits of detection ranged from 0.7 to 3.5ng/mL and from 7.9 to 35.3ng/g for four TCs surface in surface water and milk samples, respectively.