Simultaneous derivatization and dispersive liquid-liquid microextraction of anilines in different samples followed by gas chromatography-flame ionization detection

A new method based on simultaneous derivatization and dispersive liquid-liquid microextraction in one step is developed for determination of five anilines in different aqueous samples. In this method, acetonitrile containing microlitre-level of butylchloroformate was rapidly injected into aqueous sample by a syringe. After centrifugation of the cloudy solution, the fine droplets of the butylchloroformate containing the derivatized analytes were sedimented in the bottom of the conical test tube. Then, 0.5 mu L of the settled phase was injected into gas chromatography-Flame ionization detector. Under optimum conditions the enrichment factors, extraction recoveries and enhancement factors were high and ranged between 197 and 298, 47 and 69%, and 4.7and 6.2, respectively. Linearity was observed in the range of 10-10,000 mu g L-1 (except for 4-chloroaniline), and the relative standard deviations (RSD %) were lower than 5.2% (n=6). The limits of detection of the six anilines ranged from 1 to 3 mu g L-1. Different aqueous samples including tap, river and well waters as well as wastewaters were successfully analyzed. In this method the extraction solvent and derivatization agent are the same and the derivatization reaction was carried out under mild conditions. This method has several advantages over other reported techniques, being very simple, rapid and less hazardous for the environment. (C) 2012 Elsevier B.V. All rights reserved.