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...

Categories: Data; Tags: Geochemistry, Temperate Northern Atlantic, Temperate Northern Pacific, U.S. Geological Survey, USGS, All tags... biogeochemistry, carbon cycle, carbon cycling, carbon dioxide, carbon isotope analysis, cavity ring-down spectroscopy, eastern continental margin of India, environment, gas hydrate resources, geochemical data, geochemistry, geochemistry, isotope geochemistry, marine chemistry, methane, methane hydrate, northern Cascadia margin, northern US Atlantic margin, ocean characteristics, oceanography, oceans, sediment geochemistry, stable isotopes, Fewer tags