Ion pair solid phase extraction for the indirect determination of gatifloxacin by flow injection flame atomic absorption spectrometry

摘要

A flow injection flame atomic absorption spectrometry (FAAS) method with on-line ion pair solid-phase extraction was developed for the indirect determination of gatifloxacin. In a flow injection system, gatifloxacin reacted first with Fe(III) to form a 2:1 complex cation, then the cation reacted with ClO4- to form a neutral ion pair complex of gatifloxacin-Fe(III)-ClO4 and was adsorbed on a C-18 solid phase extraction column, while excessive Fe(III) was washed with H2O to waste. The ion pair complex adsorbed was eluted with a mixture of ethanol, water, and acetonitrile (48:32:20, v/v/v), Fe(III) in t e comp ex was an determined with FAAS. The optimization of various experimental conditions was investigated. With a reaction and extraction time of 60 seconds, the calibration curve was linear, ranging from 0.05 to 12.50 mu g mL(-1) with a relative standard deviation of 2.0% (n = 11, c = 5.0 mu g mL(-1) and the detection limit for gati floxacin was 0.02 mu g mL(-1). The analytical frequency was 24 samples per hour. The method was validated by the determination of gatifloxacin in capsules and tablets, and the recoveries obtained were 95-106%. This procedure not only provides a sensitive analytical method for gatifloxacin determination, but also offers a new approach for the application of FAAS in the indirect determination of organic species.