Characterization of volatile and semivolatile compounds in waste landfill leachates using stir bar sorptive extraction-GC/MS.

Stir bar sorptive extraction in combination with thermal desorption coupled online to capillary gas chromatography-mass spectrometry was applied to investigate volatile and semivolatile fractions in two waste leachate samples: old and fresh ones. The present study helps to improve our knowledge of waste leachate organic composition. The aim is to then make use of this knowledge afterwards in order to generate more reliable and specific treatment processes for waste leachates and thus to respect the environmental statute law regarding their rejection. The volatile and semivolatile compounds appeared to be mainly anthropogenic in origin. Moreover, lactic acid and cyclic octaatomic sulfur could potentially be used as microbiological activity indicators, since they occur during organic matter degradation processes within waste leachates.

Identification of new odorous compounds in Swedish water: mixed haloanisoles and phenolic precursors.

Mixed chlorobromoanisoles have recently been recognized as new potential odorous compounds in tap water. The odour threshold concentrations (OTCs) of these compounds are close to the sub ng/L (ppt) and associated descriptors are "earthy, musty, rubber". During a "swampy, musty" episode in water of the Norrtälje district (Sweden), 2,4,6-mixed chlorobromoanisoles and their phenolic precursors were identified. These compounds were synthesised in order to quantify them in different types of waters, Samplings were performed during two different seasons. Results show that whatever the season, mixed haloanisoles and their precursors were present. Chlorination, biofilm activity and residence time in the distribution system seem to be critical factors for the appearance of such compounds.

Optimization of stir bar sorptive extraction applied to the determination of odorous compounds in drinking water.

The off-flavour compounds 2-methylisoborneol (MIB), geosmin, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, 2,3,4-trichloroanisole and 2,4,6-tribromoanisole were analyzed in water samples by Stir Bar Sorptive Extraction (SBSE) followed by on-line thermal desorption (TD)-capillary GC/MS. Quantification was performed using MS in the single ion monitoring mode (SIM) with 2,4,6-trichloroanisol-D5 as internal standard. Quantification limits are 0.1 ng/l to 0.2 ng/l for the haloanisoles, 0.5 ng/l for geosmin and 1 ng/l for MIB. The relative standard deviations at the quantification limit are ranging from 7 to 14.6%. SBSE-recovery was evaluated by spiking real water samples and varied from 87 to 117%. More than twenty samples per day can be analyzed by SBSE-TD-capillary GC-MS. The same technique in combination with olfactometry was used to elucidate unknown odorous compounds in water samples.

Analysis of off-flavors in the aquatic environment by stir bar sorptive extraction-thermal desorption-capillary GC/MS/olfactometry.

The off-flavor compounds 2-methylisoborneol (MIB), geosmin, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, 2,3,4-trichloroanisole, and 2,4,6-tribromoanisole were analyzed in water samples by stir bar sorptive extraction (SBSE) followed by on-line thermal desorption (TD) capillary GC/MS. Quantification was performed using the MS in the single-ion-monitoring mode (SIM) with 2,4,6-trichloroanisole-D(5 )as internal standard. Quantification limits are 0.1-0.2 ng L(-1) for the haloanisoles, 0.5 ng L(-1) for geosmin, and 1 ng L(-1) for MIB. The relative standard deviations at the quantification limit ranged from 7 to 14.6%. SBSE recovery was evaluated by spiking real water samples and varied from 87 to 117%. More than twenty samples per day can be analyzed by SBSE-TD-capillary GC-MS. The same technique in combination with olfactometry was used to elucidate unknown odorous compounds in water samples.