Details zur Publikation
|Titel (primär)||Expanding the calibration range of compound-specific chlorine isotope analysis by the preparation of a 37Cl-enriched tetrachloroethylene|
|Autor||Buchner, D.; Martin, P.R.; Scheckenbach, J.; Kümmel, S.; Gelman, F.; Haderlein, S.B.|
|Journal / Serie||Rapid Communications in Mass Spectrometry|
The recent development of reliable GC/qMS methods for δ37Cl compound-specific stable isotope analysis (CSIA) paves the way for dual carbon–chlorine isotope analysis of chlorinated ethenes and thus allows deeper insights into underlying transformation processes/mechanisms. A two-point calibration is indispensable for the precise and correct conversion of raw data to the international δ37ClSMOC scale. The currently available calibration standards for tetrachloroethylene (PCE) span only a very narrow range from −2.52‰ (EIL2) to +0.29‰ (EIL1), which is considerably smaller than observed δ37Cl isotope enrichment in (bio-)transformation studies (up to 12‰).
We describe the preparation and evaluation of a new 37Cl-enriched PCE standard to avoid bias in δ37Cl CSIA arising from extrapolation beyond the calibration range. The preparation comprised: (i) partial PCE reduction by zero-valent zinc in a system of PCE, ethanol (initial volume ratio 3/5) and trace amounts of water followed by (ii) liquid–liquid extraction and (iii) a subsequent fractional distillation to purify the 37Cl-enriched PCE.
The obtained PCE (PCEenriched) showed a purity of 98.8% (mole fraction) and a δ37ClSMOC value of +10.8 ± 0.5‰. The evaluation of an experimental dataset with and without extrapolation showed no significant variation.
The new PCE standard (PCEenriched) expands the calibration range to 13.3‰ (previously 2.8‰) and thus prevents potential bias introduced by extrapolation beyond the calibration range.
|Buchner, D., Martin, P.R., Scheckenbach, J., Kümmel, S., Gelman, F., Haderlein, S.B. (2022):
Expanding the calibration range of compound-specific chlorine isotope analysis by the preparation of a 37Cl-enriched tetrachloroethylene
Rapid Commun. Mass Spectrom. 36 (21), e9378