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

B. E. Brumfield; M. C. Phillips

doi:10.1039/c7an00223h

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 journal › Article › peer-review

10 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 language	English (US)
Pages (from-to)	2354-2362
Number of pages	9
Journal	Analyst
Volume	142
Issue number	13
DOIs	https://doi.org/10.1039/c7an00223h
State	Published - Jul 7 2017
Externally published	Yes

ASJC Scopus subject areas

Analytical Chemistry
Biochemistry
Environmental Chemistry
Spectroscopy
Electrochemistry

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

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.",

author = "Brumfield, {B. E.} and Phillips, {M. C.}",

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AU - Brumfield, B. E.

AU - Phillips, M. C.

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N2 - 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.

AB - 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.

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

Abstract

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