HPLC determination of enoxacin, ciprofloxacin, norfloxacin and ofloxacin with photoinduced fluorimetric (PIF) detection and multiemission scanning: application to urine and serum.

The fluorescence emission of the fluoroquinolones enoxacin (ENO), ciprofloxacin (CIPRO), norfloxacin (NOR) and ofloxacin (OFLO) notably increased by UV irradiation during few minutes, in ethanolic-water medium. An HPLC method has been developed, for the determination of these fluoroquinolones, based in the separation of the formed irradiation photoproducts. Optimization of the analytical wavelengths has been carried out by fast multiemission scanning fluorescence detection. The highest sensitivity has been found when measuring at emission wavelengths of 407 and 490 nm, for ENO and OFLO, respectively, and at 444 nm for both NOR and CIPRO (exciting at 277 nm). According to the criterium of Clayton, using 0.05 as false positive and false negative error assurance probabilities, detection limits of 7.3, 6.0, 6.3 and 14.5 ng/mL, for ENO, NOR, CIPRO and OFLO, respectively, have been found. Urine and serum samples have been successfully analyzed, with recovery values ranging among 99-97% and 98-103%, for urine and serum, respectively.