Hollow fiber supported liquid-phase microextraction using ionic liquid as extractant for preconcentration of benzene, toluene, ethylbenzene and xylenes from water sample with gas chromatography-hydrogen flame ionization detection

A novel method has been developed for the analysis of benzene, toluene, ethyl-benzene, and o-, m- and p-xylenes (BTEXs) in water using hollow fiber supported liquid-phase microextraction (HF-LPME) followed by gas chromatography-hydrogen flame ionization detection. Ionic liquid 1-buty1-3-methy-limidazolium hexafluorophosphate ([BMIM][PF6]) was acted as the extractant for extraction and preconcentration of BTEXs from aqueous samples, and a porous-walled polypropylene hollow fiber was utilized to stabilize and protect [BMIMI[PF6] during the extraction process. Various parameters that affect extraction efficiency were investigated in detail, and the optimized experimental conditions were as follows: 8 mu L of [BMIM][PF6] as extraction solvent for the target analytes in 20 mL of sample solution, 30 min of extraction time, a stirring rate of 1400 rpm and 15% NaCl (w/v) in aqueous sample at 25 degrees C (ambient temperature). The recovery was found to be 90.0-111.5% with RSD (n = 5) of 1.3-5.4%, and the detection limits (S/N =3) were in the range of 2.7-4.0 mu g/L. The proposed method was simple, cheap, rapid, sensitive and environmentally benign, and could act as an alternative to techniques for BTEXs analysis with expensive instrumentations. (C) 2011 Elsevier B.V. All rights reserved.