Simultaneous determination of 22 volatile organic compounds, methyl- tert-butyl ether, 1,4-dioxane, 2-methylisoborneol and geosmin in water by headspace solid phase microextraction-gas chromatography–mass spectrometry

Abstract

A method for the simultaneous determination of 22 volatile organic compounds (VOCs), methyl- tert-butyl ether (MTBE), 1,4-dioxane, 2-methylisoborneol (2-MIB) and geosmin in water by headspace solid phase microextraction (SPME)-gas chromatography–mass spectrometry (GC–MS) is described. Three types of SPME fibers (carboxen (CAR)/polydimethylsiloxane (PDMS), divinylbenzene (DVB)/PDMS and 100-μm PDMS) were evaluated to achieve the method detection limits and linear range required in Japanese water regulation. A 100-μm PDMS was found to be the best coating to obtain a wide range of linearity for the target compounds in multiple-component system. CAR/PDMS and DVB/PDMS of adsorbent type fibers showed a narrow linear range for 22 VOCs, MTBE and 1,4-dioxane at the μg/l levels due to the limited capacity. The detection limits of this method were 0.01–0.05 μg/l for 22 VOCs, 0.01 μg/l for MTBE, 1.2 μg/l for 1,4-dioxane, 0.6 ng/l for 2-MIB and 0.3 ng/l for geosmin. The recoveries of 22 VOCs and MTBE from a river water sample spiked at 1 μg/l were between 93.7 and 104.0%, with R.S.D. values of between 1.7 and 9.5%. Those of 1,4-dioxane, 2-MIB and geosmin at 5 μg/l, 10 ng/l and 10 ng/l, respectively, were 109.1, 95.9 and 97.4%, with R.S.D. values of 2.0, 5.6 and 1.8%. The method provided linear range from 0.1 to 100 μg/l for 21 VOCs and MTBE, 0.1 to 50 μg/l for m, p-xylene, 5 to 100 μg/l for 1-4dioxane and 1 to 100 ng/l for 2-MIB and geosmin.