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-butyl-3-methy-limidazolium hexafluorophosphate ([BMIM][PF(6)]) 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 [BMIM][PF(6)] during the extraction process. Various parameters that affect extraction efficiency were investigated in detail, and the optimized experimental conditions were as follows: 8 μL of [BMIM][PF(6)] 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°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 μg/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.