5 May 2017 MIR hollow waveguide (HWG) isotope ratio analyzer for environmental applications
Author Affiliations +
An advanced commercial Mid-InfraRed Isotope Ratio (IR2) analyzer was developed in Arrow Grand Technologies based on hollow waveguide (HWG) as the sample tube. The stable carbon isotope ratio, i.e. δ13C, was obtained by measuring the selected CO2 absorption peaks in the MIR. Combined with a GC and a combustor, it has been successfully employed to measure compound specific δ13C isotope ratios in the field. By using both the 1- pass HWG and 5-path HWG, we are able to measure δ13C isotope ratio at a broad CO2 concentration of 300 ppm-37,500 ppm. Here, we demonstrate its applications in environmental studies. The δ13C isotope ratio and concentration of CO2 exhaled by soil samples was measured in real time with the isotope analyzer. The concentration was found to change with the time. We also convert the Dissolved Inorganic Carbon (DIC) into CO2, and then measure the δ13C isotope ratio with an accuracy of better than 0.3 ‰ (1 σ) with a 6 min test time and 1 ml sample usage. Tap water, NaHCO3 solvent, coca, and even beer were tested. Lastly, the 13C isotope ratio of CO2 exhaled by human beings was obtained <10 seconds after simply blowing the exhaled CO2 into a tube with an accuracy of 0.5‰ (1 σ) without sample preconditioning. In summary, a commercial HWG isotope analyzer was demonstrated to be able to perform environmental and health studies with a high accuracy (~0.3 ‰/Hz1/2 1 σ), fast sampling rate (up to 10 Hz), low sample consumption (~1 ml), and broad CO2 concentration range (300 ppm-37,500 ppm).
Conference Presentation
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Zhenyou Wang, Zhenyou Wang, Yan Zhuang, Yan Zhuang, Andrei Deev, Andrei Deev, Sheng Wu, Sheng Wu, } "MIR hollow waveguide (HWG) isotope ratio analyzer for environmental applications", Proc. SPIE 10210, Next-Generation Spectroscopic Technologies X, 1021009 (5 May 2017); doi: 10.1117/12.2262914; https://doi.org/10.1117/12.2262914

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