title: Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.
abstract: Compound-specific chlorine isotope analysis of tetrachloromethane (CCl4) and trichloromethane (CHCl3) was explored by both, gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and GC-quadrupole MS (GC-qMS), where GC-qMS was validated in an interlaboratory comparison between Munich and Neuchâtel with the same type of commercial GC-qMS instrument. GC-IRMS measurements analyzed CCl isotopologue ions, whereas GC-qMS analyzed the isotopologue ions CCl3, CCl2, CCl (of CCl4) and CHCl3, CHCl2, CHCl (of CHCl3), respectively. Lowest amount dependence (good linearity) was obtained (i) in H-containing fragment ions where interference of35Cl- to37Cl-containing ions was avoided; (ii) with tuning parameters favoring one predominant rather than multiple fragment ions in the mass spectra. Optimized GC-qMS parameters (dwell time 70 ms, 2 most abundant ions) resulted in standard deviations of 0.2‰ (CHCl3) and 0.4‰ (CCl4), which are only about twice as large as 0.1‰ and 0.2‰ for GC-IRMS. To compare also the trueness of both methods and laboratories, samples from CCl4and CHCl3degradation experiments were analyzed and calibrated against isotopically different reference standards for both CCl4and CHCl3(two of each). Excellent agreement confirms that true results can be obtained by both methods provided that a consistent set of isotopically characterized reference materials is used.
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Heckel
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB) , C/Martí i Franquès, s/n 08028, Barcelona, Spain.
authors.forename: Diana
authors.initials: D
authors.lastname: Rodríguez-Fernández
authors.affiliation: Centre d'Hydrogéologie et de Géothermie (CHYN), Université de Neuchâtel (UNINE) , Rue Emile-Argand 11, Neuchâtel 2000, Switzerland.
authors.forename: Clara
authors.identifier: 0000-0003-1480-2744
authors.initials: C
authors.lastname: Torrentó
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Meyer
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB) , C/Martí i Franquès, s/n 08028, Barcelona, Spain.|Centre d'Hydrogéologie et de Géothermie (CHYN), Université de Neuchâtel (UNINE) , Rue Emile-Argand 11, Neuchâtel 2000, Switzerland.
authors.forename: Jordi
authors.identifier: 0000-0001-9492-7306
authors.initials: J
authors.lastname: Palau
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB) , C/Martí i Franquès, s/n 08028, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Domènech
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB) , C/Martí i Franquès, s/n 08028, Barcelona, Spain.
authors.forename: Mònica
authors.initials: M
authors.lastname: Rosell
authors.affiliation: Grup de Mineralogia Aplicada i Geoquímica de Fluids, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB) , C/Martí i Franquès, s/n 08028, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Soler
authors.affiliation: Centre d'Hydrogéologie et de Géothermie (CHYN), Université de Neuchâtel (UNINE) , Rue Emile-Argand 11, Neuchâtel 2000, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hunkeler
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München , Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Martin
authors.identifier: 0000-0003-4746-9052
authors.initials: M
authors.lastname: Elsner