COMPARISON OF PROGRAMMABLE VERSUS SINGLE-WAVELENGTH FLUORESCENCE FOR THE DETECTION OF 3 FLUOROQUINOLONE ANTIBACTERIALS ISOLATED FROM FORTIFIED CHICKEN LIVER USING COUPLED ON LINE MICRODIALYSIS AND HPLC

A recently introduced programmable fluorescence detector was compared with a single wavelength fluorescence detector for quantification of f luoroquinolone (FQ) antibacterial agents, which have widely varying sp ectral characteristics. The two detectors were connected in parallel t o an HPLC system to test their performance characteristics. With singl e wavelength detection, two FQs, flumequine and oxolinic acid could be detected at an emission wavelength of 358 mn in a single chromatogram while a third FQ, sarafloxacin, was not observed at that wavelength. Similarly, when the detector was optimized for sarafloxacin emission a t 440 nm, the other two compounds were undetected. In contrast, all th ree FQs were quantified at their individual maxima in a single run usi ng the programmable fluorescence detection. The applicability of an HP LC - programmable fluorescence detector, in combination with on-line m icrodialysis, also was evaluated using chicken liver fortified at low ppb levels with the three FQs, After on-line microdialysis sample clea n up, the resultant HPLC chromatograms were free of background interfe rence enabling the programmable detector to optimize the quantitation of the three analytes in a single run. The limit of quantification (LO Q) determined for each FQ was 1.0 ppb and the limit of detection (LOD) was 0.2 ppb, an order lower in magnitude than was obtainable with sin gle wavelength detection.