Simultaneous determination of the potential carcinogen 1,4-dioxane and malodorous alkyl-1,3-dioxanes and alkyl-1,3-dioxolanes in environmental waters by solid-phase extraction and gas chromatography tandem mass spectrometry.

1,4-dioxane is a synthetic industrial solvent used in various industrial processes, and it is a probable human carcinogen whose presence in the aquatic environment is frequently reported. Alkyl-1,3-dioxanes and alkyl-1,3-dioxolanes are compounds that have been identified as causing several odor episodes in waters over the last years, with the result of downtime of drinking water treatment plants. According to published studies, some of these episodes may be caused either by resins synthesis processes, or by industrial residues added to dehydrated sludge in wastewater treatment plants (WWTPs) in order to increase biogas production efficiency. Analytical methods based on closed loop stripping analysis (CLSA) are routinely used when taste and odor events appear, but this technique has demonstrated to be unsuitable to determine 1,4-dioxane at trace levels. In this context, drinking water companies tend to focus on determining odorous compounds, but not on those compounds that are potentially harmful. The suitability of a SPE method and further analysis by GC/MS-MS to simultaneously determine 1,4-dioxane and alkyl-1,3-dioxanes and dioxolanes has been demonstrated. Recoveries in surface waters spiked at 25ng/L ranged from 76% to 105%, whereas method quantification limits (MQLs) varied from 0.7 to 26ng/L for dioxanes, and dioxolanes and 50ng/L for 1,4-dioxane. Uncertainties were evaluated at two different concentrations, 0.02μg/L and 0.4μg/L, with values of 25% for 1,4-dioxane, and of 16-28% for alkyl-1,3-dioxanes and alkyl-1,3-dioxolanes for the later. The methodology has been successfully applied to samples from the aquifer of the Llobregat River (NE. Spain).