Stable carbon isotope ratio of carbon dioxide (δ13CCO2) is used as an important indicator in the researches for global climate change and carbon capture and sequestration technology. The δ13C value has been usually analyzed with Isotope Ratio Mass Spectrometer (IRMS). Recently, the use of Laser Absorption Spectrometry (LAS) is increasing because of the cost efficiency and field applicability. The purpose of this study was to suggest practical procedures to prepare laboratory reference gases for δ13CCO2 analysis using LAS. CO2 gas was adjusted to have the concentrations within the analytical range. Then, the concentration of CO2 was assessed in a lab approved by the Korea Laboratory Accreditation Scheme and the δ13CCO value was measured by IRMS. When the instrument ran over 12 hours, the δ13C values were drifted up to ±10‰ if the concentration of CO2 was shifted up to 1.0% of relative standard deviation. Therefore, periodical investigation of analytical suitability and correction should be conducted. Because δ13CCO2 showed the dependency on CO2 concentration, we suggested the equation for calibrating the concentration effect. After calibration, δ13CCO2 was well matched with the result of IRMS within ±0.52‰.
All Science Journal Classification (ASJC) codes
- Environmental Science (miscellaneous)
- Economic Geology