Use of flat-sheet membrane extraction with a sorbent interface for solvent-free determination of BTEX in water

초록

An analytical method for solvent-free determination of benzene, toluene, ethylbenzene, and xylenes (BTEX) in water using flat-sheet membrane extraction with a sorbent interface (MESI) coupled to GC-MS was established by optimizing the flow rates of the donor (20 ml water) and acceptor (helium) phases and extraction temperature. BTEX compounds permeated through a nonporous silicone membrane and evaporated into the acceptor phase were purged into a cryofocusing trap (-30 degrees C) with helium gas. Enriched compounds were thermally desorbed into a capillary gas chromatograph and detected with a mass spectrometer. The optimum flow rates of the donor and acceptor phases were set at 1.5 and 55 ml min(-1), respectively, and the temperature of the membrane extraction module was maintained within the 28-30 degrees C range. The method as established showed low method detection limits (MDLs:similar to 0.1 mu g l(-1)) and highly linear calibration curves (r(2) >0.998) for all of the four compounds. High repeatability (relative standard deviation <similar to 5%) and a reasonably high extraction recovery (62-78%), after a single pass of the sample through the extraction module, also were established. Further, the method's high compatibility with the purge and trap (P&T) method indicates its applicability to field measurement. Other advantages include rapidity, simplicity, and a ready extendibility to automated on-line monitoring. (C) 2012 Elsevier B.V. All rights reserved.

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