Chemiluminescence determination of fluoroquinolones using Fenton system in the presence of terbium(iii) ions

Abstract

A simple new chemiluminescent, CL, method is described for the determination of fluoroquinolones such as: ciprofloxacin (CF), norfloxacin (NF), and ofloxacin (OF). This method is based on the measurement of terbium(III) emission. This emission follows an energy transfer to the uncomplexed terbium(III) ions from the excited products of fluoroquinolone oxidations. Under optimum conditions, calibration graphs were obtained for 2 × 10⁻⁸–2 × 10⁻⁶ mol L⁻¹ of NF; 3 × 10⁻⁸–2 × 10⁻⁶ mol L⁻¹ of CF and 4 × 10⁻⁷–5 × 10⁻⁵ mol L⁻¹ of OF. The detection limits are 7 × 10⁻⁹ mol L⁻¹norfloxacin, 1 × 10⁻⁸ mol L⁻¹ciprofloxacin and 1.5 × 10⁻⁷ mol L⁻¹ofloxacin. The method was successfully applied to the determination of these drugs in pharmaceutical formulations.