Abstract
Levofloxacin{(–)-(S)-9-fluoro-2,3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acid} is a synthetic fluorinated quinolone derivative, having activity against both Gram (+) and Gram (–) bacteria (aerobic and anaerobic) through inhibition of their DNA gyrase. In this paper, a simple flow injection chemiluminescence with luminol–hydrogen peroxide system was described for determining levofloxacin. The chemiluminescence intensity in the presence of levofloxacin was remarkably enhanced compared with that in the absence of it. Under the optimum reaction conditions the chemiluminescence increment produced was proportional to the concentration of levofloxacin in the range of 1.0–700.0 ng ml–1 (R2═0.9992), with a detection limit of 0.3 ng ml–1 (3σ). At the flow rate of 2.0 ml min–1, the whole process including sampling and washing could be completed in 0.5 min offering the sampling efficiency of 120 times h–1 accordingly, and the relative standard deviation (RSD) was less than 3.0% (n═5). The recovery for the levofloxacin samples was from 95.9% to 104.5%. It was satisfactory for the application to determine levofloxacin in pharmaceutical preparations, human urine and serum samples.