Hollow-fibre liquid-phase microextraction of phthalate esters from water

A simple and efficient liquid-phase microextraction (LPME) technique using a hollow-fibre membrane, in conjunction with gas chromatography–mass spectrometry has been developed for the extraction and analysis of six phthalate esters in water samples. Parameters such as extraction solvent, agitation of the sample, salt addition and extraction time were controlled and optimised. The developed protocol was found to yield a linear calibration curve in the concentration range from 0.02 to 10 μg l−1 for most target analytes and the limits of detection were in the low μg l−1 level, ranging between 0.005 and 0.1 μg l−1. The repeatability of the method varied between 4% and 11%. Under the present experimental conditions, the performance of the method was found comparable to that of solid-phase microextraction (SPME). The advantage of the proposed method over SPME was that it eliminated carry-over of analytes between runs. The applicability of the developed hollow-fibre LPME method and SPME was demonstrated for real water samples. The ability of both microextraction methods to concentrate many organic analytes was demonstrated as both methods allowed the confirmation of the presence of an extra contaminant (ethyl p-ethoxybenzoate) in bottled mineral water samples.