An analytical method based on on-line solid-phase extraction coupled to liquid chromatography with fluorescence detection has been developed to determine quinolones in tap water and human urine. A home-made setup was used to percolate 10\u00a0mL of sample through a solid-phase extraction column. Analytes were retained onto the sorbent by an anion exchange mechanism which ensures an optimum compatibility with the subsequent chromatographic separation. A C-18 column containing core-shell particles (2.6\u00a0\u03bcm) was used to achieve peak efficiencies up to 200,000\u00a0plates\/m, at a flow rate of 1.2\u00a0mL\/min and without the need for special pumps. The method allowed the determination of 11 quinolones directly in tap water samples in less than 20\u00a0min and with limits of detection ranging between 7 and 110\u00a0ng\/L. The sensitivity achieved made possible the direct determination of 9 quinolones in human urine without any sample treatment, just dilution with water. Relative recoveries between 94 and 109% were obtained meaning that the matrix effect in human urine is negligible after dilution. Satisfactory results were also obtained in terms of precision since relative standard deviations were always below 13%.<\/p>\n","protected":false},"excerpt":{"rendered":"
An analytical method based on on-line solid-phase extraction coupled to liquid chromatography with fluorescence detection has been developed to determine quinolones in tap water and human urine. A home-made setup was used to percolate 10\u00a0mL of sample through a solid-phase … Continue reading