title: Headspace solid phase microextraction--GC/C-IRMS for delta13CVPDB measurements of mono-aromatic hydrocarbons using EA-IRMS calibration.
abstract: This work aims at comparing the delta(13)C(VPDB) of mono-aromatic hydrocarbons benzene, toluene, ethylbenzene and xylene isomers (BTEX) measured by elemental analyser (EA)-isotope ratio mass spectrometer (IRMS) with the delta(13)C(VPDB) measured on the same compounds by headspace solid phase microextraction - GC/C-IRMS (hSPME - GC/C-IRMS) with the final goal of using these compounds as internal standards on the latter system. The EA-IRMS measurements were done using calcium and lithium carbonate isotopic reference materials: NBS19 and L-SVEC for establishing the delta(13)C(VPDB) scale. The EA-IRMS measurements with helium dilution of a set of five reference materials (USGS40, USGS41, IAEA-CH-6, IAEA-CH-3 and IAEA-601) show systematic bias of 1 per thousand relative to their assigned values. This bias due to the dilution mechanism in the used ConfloII interface device could not be avoided. As the selected hydrocarbons: BTEX could not be analysed by EA-IRMS without helium dilution, their delta(13)C(VPDB) must be corrected from this observed bias using an external calibration. The CO(2) gas calibrated using EA-IRMS without helium dilution, was used as an in-house reference for the delta(13)C(VPDB) measurements of the BTEX by the hSPME - GC/C-IRMS system. The comparison made between the delta(13)C(VPDB) measured on the same BTEX compounds by EA-IRMS (with external calibration) and by hSPME - GC/C-IRMS techniques showed good agreement.
authors.affiliation: European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium. veronique.woule-ebongue@ec.europa.eu
authors.forename: Véronique Woule
authors.initials: VW
authors.lastname: Ebongué
authors.forename: Benny
authors.initials: B
authors.lastname: Geypens
authors.forename: Michael
authors.initials: M
authors.lastname: Berglund
authors.forename: Philip
authors.initials: P
authors.lastname: Taylor
mesh_terms: D001554:Benzene / Q000032:analysis / Q000737:chemistry; D001555:Benzene Derivatives / Q000032:analysis / Q000737:chemistry; D002138:Calibration; D002245:Carbon Dioxide / Q000737:chemistry; D002247:Carbon Isotopes / Q000032:analysis; D002849:Chromatography, Gas / Q000379:methods; D004785:Environmental Pollutants / Q000737:chemistry*; D006371:Helium / Q000737:chemistry; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D013058:Mass Spectrometry / Q000379:methods; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction / Q000379:methods*; D014050:Toluene / Q000032:analysis / Q000737:chemistry; D014992:Xylenes / Q000032:analysis / Q000737:chemistry
chemical_list: D001555:Benzene Derivatives; D002247:Carbon Isotopes; D004785:Environmental Pollutants; D006841:Hydrocarbons, Aromatic; D014992:Xylenes; D002245:Carbon Dioxide; D006371:Helium; D014050:Toluene; D001554:Benzene; C004912:ethylbenzene