Comparison of methane concentration and stable carbon isotope data for natural samples analyzed by discrete sample introduction module - cavity ring down spectroscopy (DSIM-CRDS) and traditional methods
A discrete sample introduction module (DSIM) was developed and interfaced to a cavity ring-down spectrometer to enable measurements of methane and CO2 concentrations and 13C values with a commercially available cavity ring-down spectrometer (CRDS). The DSIM-CRDS system permits the analysis of limited volume (5 - 100-ml) samples ranging six orders-of-magnitude from 100% analyte to the lower limit of instrument detection (2 ppm). We demonstrate system performance for methane by comparing concentrations and 13C results obtained by the DSIM and traditional methods for a variety of sample types, including low concentration (nanomolar) seawater and high concentration (> 90%) natural gas. The expansive concentration range the CRDS is able to analyze while being packaged in a field-portable analytical system greatly enhances functionality for investigating methane and CO2 dynamics, as well as other gases measured by laser absorption spectroscopy.
Citation Information
Publication Year | 2021 |
---|---|
Title | Comparison of methane concentration and stable carbon isotope data for natural samples analyzed by discrete sample introduction module - cavity ring down spectroscopy (DSIM-CRDS) and traditional methods |
DOI | 10.5066/P99B34V1 |
Authors | John Pohlman, Michael Casso |
Product Type | Data Release |
Record Source | USGS Digital Object Identifier Catalog |
USGS Organization | Woods Hole Coastal and Marine Science Center |
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Discrete sample introduction module for quantitative and isotopic analysis of methane and other gases by cavity ring-down spectroscopy
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