title: Identification of 2,3-butanedione (diacetyl) as the compound causing odor events at trace levels in the Llobregat River and Barcelona's treated water (Spain).
abstract: A study of organic compounds imparting sweet and buttery odor problems in the Llobregat River (northeast Spain) and in treated water was conducted. Solid-phase microextraction (SPME), gas chromatography-olfactometry, and flavor profile analysis (FPA) were used as analytical methodologies to identify the compound responsible for odor incidents. 2,3-Butanedione (diacetyl) with a concentration range of 0.90-26 microg/l in river water samples entering the water treatment plant was identified as the compound causing the odor events. Flavor profile analysis establishes 0.05 microg/l as its odor threshold concentration (OTC) in water, with an odor recognition concentration of 0.20 microg/l. The analyses were carried out with SPME-GC-MS and parameters affecting SPME extraction such as selection of the fiber (carboxen-polydimethylsiloxane), extraction time (30 min), temperature (60 degrees C), and ionic strength were evaluated. Quality parameters of the optimized method gives good linearity (r2 > 0.999), a limit of detection (0.08 microg/l) similar to the OTC of the compound, and good reproducibility (R.S.D. < 20%). The SPME method was applied to identify the compound causing the odor.
authors.affiliation: AGBAR, Societat General d'Aigües de Barcelona, Passeig de Sant Joan 39, E-08009 Barcelona, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Díaz
authors.forename: Francesc
authors.initials: F
authors.lastname: Ventura
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Galceran
mesh_terms: D003931:Diacetyl / Q000032:analysis*; D005118:Extraterrestrial Environment; D008401:Gas Chromatography-Mass Spectrometry; D009812:Odorants; D015203:Reproducibility of Results; D045483:Rivers; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D003931:Diacetyl