Hollow fibre liquid phase microextraction (HFLPME) was explored for benzene, toluene, ethylbenzene and o-xylene sampling and preconcentration.
The investigation covered the effects of extraction solvent type, extraction time and ionic strength of the sample solution. Dibutyl phthalate : n-octanol (1 : 1) mixture containing n-octane as the internal standard was used as an extracting solvent. The calibration curves were from 0.36, 0.10, 0.23 and 0.27 μg l^–1 up to 50 μg ml^–1 for benzene, toluene, ethylbenzene and o-xylene, respectively, the correlation coefficients being 0.997–0.998, enrichment factors from 112 for benzene to 260 for o-xylene and the detection limits 0.22, 0.06, 0.14 and 0.16 μg l^–1 for benzene toluene, ethylbenzene and o-xylene, respectively. The repeatability of the results was acceptable with relative standard deviations up to 11.4%. A possibility to apply the proposed techniques for determination of aromatic hydrocarbons in tap water and snow was demonstrated.

Keywords: liquid phase microextraction, gas chromatography, BTEX