Application of ionic surfactant as a carrier and emulsifier agent for the microextraction of fluoroquinolones

A simple microextraction method based on emulsification of organic extraction solvent in aqueous sample using an ionic surfactant was evaluated for extraction and preconcentration of trace amounts of ofloxacin and ciprofloxacin as polar model drugs. In this method, the surfactant was used as carrier and disperser agent simultaneously. The target analytes were converted into their ion-pair complexes with Aliquat-336 and then extracted into an organic solvent (1-octanol) dispersed in aqueous solution. After extraction and phase separation, the organic solvent on top of the solution was withdrawn into the syringe and 20 mu L of it was injected into a HPLC instrument for analysis. The factors influential to extraction were investigated and optimized. Under optimum extraction conditions, the limits of detection (LODs) as small as 0.06 and 0.02 ng mL(-1) and linear dynamic range of 0.1-100 and 0.06-100 ng mL(-1) were obtained for ofloxacin and ciprofloxacin, respectively. For analysis of real samples such as waste water, river water and urine samples, solid-phase extraction (SPE) was applied prior to liquid phase microextraction in order to avoid/remove matrix effect. The obtained results indicate that the proposed method is efficient, fast and inexpensive for extraction and determination of fluoroquinolones in environmental aqueous and urine samples. (C) 2012 Elsevier B.V. All rights reserved.