Solid-phase microextraction—Gas chromatography to determine volatile organic sulfur compounds in the air at sewage treatment plants

Solid-phase microextraction (SPME) was applied to the determination of 7 volatile organic sulfur compounds (VOSCs), which were analysed by gas chromatography–mass spectrometry. The compounds studied were ethyl mercaptan (CH3CH2SH), dimethyl sulfide ((CH3)2S), carbon disulfide (CS2), propyl mercaptan (C3H8S), butyl mercaptan (C4H10S), dimethyl disulfide ((CH3)2S2) and 1-pentanethiol (C5H12S). Temperature and time conditions of SPME extraction were optimised and the method was validated, with good linearity in a calibration range between 0.1 and 1000 μg m−3. Method detection limits ranged between 0.01 and 0.08 μg m−3 and method quantification limits were between 0.10 and 0.25 μg m−3, allowing real samples taken from several different areas of a sewage treatment plant to be analysed. Repeatability of the method between samples went from 5.6% for pentanethiol up to 14.2% for carbon disulfide, and concentrations of total target compounds were found between 18 and 529 μg m−3, depending on the sampling site.