Rapid and Simple Determination of Sarafloxacin in Egg by Time-Resolved Chemiluminescence

Abstract

A new chemiluminescence method for the determination of the fluoroquinolone sarafloxacin is described. The method is based on the measurement of the chemiluminescent (CL) radiation emitted in the reaction of sarafloxacin with Ce (IV) in sulfuric acid medium and in the presence of \( \mathrm{Ru}(\mathrm{bipy})_3^{2+ } \) as sensitizer. Since the method allows the recording of the whole CL intensity-versus-time profile, the use of measurement parameters such as the maximum CL emission is possible, which is proportional to the analyte concentration. The optimum chemical and experimental conditions for the CL emission of the reaction were researched. The calibration graph was lineal in the concentration range from 5.0 to 30.0 mg L−1 of sarafloxacin. The limit of detection, according to Clayton et al. (Anal Chem 59:2506–2514, 1987), was 1.17 mg L−1. After analyzing a series of ten solutions of 10.0 mg L−1 of sarafloxacin, the estimated average concentration was 10.30 mg L−1 with a standard deviation of 0.42 mg L−1 (confidence level, 95 %). The effect on the sarafloxacin CL signal of some common excipients (sucrose, lactose, and starch) used widely in pharmaceutical preparations was also tested, as well as that of others fluoroquinolones (namely, enrofloxacin and ciprofloxacin). Finally, the proposed method was applied to the determination of sarafloxacin in different spiked egg samples by using the standard addition methodology, obtaining excellent recoveries in all cases (close to 100 %).