title: Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.
abstract: In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.
authors.affiliation: University Duisburg-Essen, Lotharstr.1, 47048, Duisburg, Germany.
authors.forename: Dorothea M
authors.initials: DM
authors.lastname: Kujawinski
authors.forename: Manuel
authors.initials: M
authors.lastname: Stephan
authors.forename: Maik A
authors.initials: MA
authors.lastname: Jochmann
authors.forename: Karen
authors.initials: K
authors.lastname: Krajenke
authors.forename: Joe
authors.initials: J
authors.lastname: Haas
authors.forename: Torsten C
authors.initials: TC
authors.lastname: Schmidt
mesh_terms: D002247:Carbon Isotopes; D003903:Deuterium; D004784:Environmental Monitoring / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D005742:Gasoline / Q000032:analysis; D057230:Limit of Detection; D008738:Methyl Ethers / Q000032:analysis*; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis* / Q000592:standards
chemical_list: D002247:Carbon Isotopes; D005742:Gasoline; D008738:Methyl Ethers; D014874:Water Pollutants, Chemical; C043243:methyl tert-butyl ether; C096680:tertiary-amyl methyl ether; D003903:Deuterium