Determination of volatile organic compounds in water samples using membrane-solid phase microextraction (M-SPME) (headspace version)

Abstract

The results of a study on the use of membrane-solid phase microextraction (M-SPME) for sampling volatile organic compounds (VOCs) from the headspace above the liquid medium are presented. The sampled VOCs were subsequently quantified by gas chromatography (GC). Two systems were compared in this study, i.e. a novel two-phase sorption system (M-SPME), and a commercial fibre. Headspace sampling using SPME was optimized with respect to sample temperature, extraction time and the content of a salting-out agent (independently vs. each parameter). Under the optimized conditions, extraction with the M-SPME fibre yielded a limit of detection (LOD) of 0.011 µg L⁻¹. This value is comparable with LOD achieved with a commercial fibre under its own optimum conditions. However, using the M-SPME sample preparation procedure developed in this work, a broad linear range from 0.5 to 100 µg L⁻¹ was obtained, while isolation with a commercial fibre resulted in a linear range up to ca. 25 µg L⁻¹ only. Finally, the suitability of the novel fibre for VOC determination was proved by conducting measurements on real samples.