Back to Search
Start Over
Vapor Pressure Isotope Effects in Halogenated Organic Compounds and Alcohols Dissolved in Water
- Source :
- Analytical chemistry. 88(24)
- Publication Year :
- 2017
-
Abstract
- Volatilization causes changes in the isotopic composition of organic compounds as a result of different vapor pressures of molecules containing heavy and light isotopes. Both normal and inverse vapor pressure isotope effects (VPIE) have been observed, depending on molecular interactions in the liquid phase and the investigated element. Previous studies have focused mostly on pure compound volatilization or on compounds dissolved in organic liquids. Environmentally relevant scenarios, such as isotope fractionation during volatilization of organics from open water surfaces, have largely been neglected. In the current study, open-system volatilization experiments (focusing thereby on kinetic/-nonequilibrium effects) were carried out at ambient temperatures for trichloromethane, trichloroethene, trichlorofluoromethane, trichlorotrifluoroethane, methanol, and ethanol dissolved in water and, if not previously reported in the literature for these compounds, for volatilization from pure liquids. Stable carbon isotopic signatures were measured using continuous flow isotope ratio mass spectrometry. The results demonstrate that volatilization of the four halogenated compounds from water does not cause a measurable change in the carbon isotopic composition, whereas for pure-phase evaporation, significant inverse isotope effects are consistently observed (+0.3 ‰ε+ 1.7 ‰). In contrast, methanol and ethanol showed normal isotope effects for evaporation of pure organic liquids (-3.9 ‰ and -1.9 ‰) and for volatilization of compounds dissolved in water (-4.4 ‰ and -2.9 ‰), respectively. This absence of measurable carbon isotope fractionation considerably facilitates the application of isotopic techniques for extraction of field samples and preconcentration of organohalogens-known to be important pollutants in groundwater and in the atmosphere.
- Subjects :
- Volatilisation
Isotope
Trichlorofluoromethane
Vapor pressure
Inorganic chemistry
chemistry.chemical_element
010501 environmental sciences
010402 general chemistry
01 natural sciences
3. Good health
0104 chemical sciences
Analytical Chemistry
chemistry.chemical_compound
Isotope fractionation
chemistry
13. Climate action
Environmental chemistry
Kinetic isotope effect
Methanol
Carbon
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 15206882
- Volume :
- 88
- Issue :
- 24
- Database :
- OpenAIRE
- Journal :
- Analytical chemistry
- Accession number :
- edsair.doi.dedup.....1638d3d25f259fcab028bbc0e0c9243a