Simultaneous determination of five fluoroquinolones by the selective high performance liquid chromatography associating with sensitive resonance light scattering and mechanism study

A novel and selective high performance liquid chromatography (HPLC) technique incorporating resonance light scattering (RLS) detection approach was developed for the determination of five fluoroquinolones (FQS) synchronously for the first time, including enoxacin (ENO), ofloxacin (OFLX), lomefloxacin (LMLX), gatifloxacin (GFLX) and sparfloxacin (SPLX). In pH 4.4 Britton - Robinson (BR) buffer medium, the ENO, OFLX, LMLX, GFLX, SPLX separated by HPLC reacted with erythrosine (ERY) to form 1:1 ion-association complexes, which led to significant enhancement of RLS. The maximum RLS wavelength of the ion-association complexes located at 330 nm. The detection limits of ENO, OFLX, LMLX, GFLX, SPLX were 5.1 ng·mL− 1, 3.1 ng·mL− 1, 4.2 ng·mL− 1, 3.8 ng·mL− 1, 17.5 ng·mL− 1 respectively at a signal-to-noise ratio of 3. In this work, the optimum experimental conditions and reaction mechanism were investigated in detail. The proposed method could be applied to the determination of ENO, OFLX, LMLX, GFLX, SPLX in water samples synchronously and the results were satisfactory.