Quantitative isotopic measurements of gas-phase alcohol mixtures using a broadly tunable swept external cavity quantum cascade laser

B. E. Brumfield, M. C. Phillips

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

A swept-ECQCL is used for broadband IR spectroscopy of isotopic mixtures of CH3OH, CH3OD, CH3CH2OH, and CH3CH2OD in a static gas cell over a wavelength range of 9.5 to 10.4 μm. A weighted least squares fitting approach with quantitative library spectra illustrates that significant spectral congestion does not negatively impact the ability for in situ quantification of large isotopic species in a mixture. The noise equivalent concentrations for CH3OH, CH3OD, CH3CH2OH, and CH3CH2OD are 19 ppbv m, 28 ppbv m, 450 ppbv m, and 350 ppbv m respectively for a 50 seconds integration time. Based on the observed NECs, isotopic precisions of 0.07‰ and 0.79‰ for a 50 s integration time are calculated for measurements of the [MeOD]/[MeOH] and [EtOD]/[EtOH] isotope ratios, respectively, for the species concentrations in the gas cell.

Original languageEnglish (US)
Pages (from-to)2354-2362
Number of pages9
JournalAnalyst
Volume142
Issue number13
DOIs
StatePublished - Jul 7 2017
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

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