• Title/Summary/Keyword: Off-axis integrated cavity output spectroscopy

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Analysis of Acetone Absorption Spectra Using Off-axis Integrated Cavity Output Spectroscopy for a Real-time Breath Test

  • Lim Lee;Yonghee Kim;Byung Jae Chun;Taek-Soo Kim;Seung-Kyu Park;Kwang-Hoon Ko;Ki-Hee Song;Hyunmin Park
    • Current Optics and Photonics
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    • v.7 no.6
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    • pp.761-765
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    • 2023
  • We analyzed the absorption spectra of acetone in the 3.37 ㎛ mid-infrared range using the off-axis integrated cavity output spectroscopy technique to develop a real-time, in-line breath analysis device. The linear relationship between acetone concentration and absorption increase was confirmed as 0.32%/ppm, indicating that the developed device allows for a quantitative analysis of acetone concentration in exhaled breath. To further confirm the feasibility of using our device for breath analysis, we measured the acetone concentration of human breath samples at the sub-ppm level.

Applications of Isotope Ratio Infrared Spectroscopy (IRIS) to Analysis of Stable Isotopic Compositions of Liquid Water (동위원소비 적외선 분광법(IRIS)을 이용한 물 안정동위원소 분석)

  • Jung, Youn-Young;Koh, Dong-Chan;Lee, Jeonghoon;Ko, Kyung-Seok
    • Economic and Environmental Geology
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    • v.46 no.6
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    • pp.495-508
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    • 2013
  • Recently, stable isotopes (${\delta}^{18}O$ and ${\delta}D$) of water are increasingly analyzed using laser-based technologies. These methods have advantages over Isotope Ratio Mass Spectrometry (IRMS) in that they can be used for in-situ measurements and require much less maintenance and preparation work. Two types of laser-based methods are currently available, which have different analytical principles; OA-ICOS (off-axis integrated cavity output spectroscopy) and WS-CRDS (wavelength-scanned cavity ring-down spectroscopy). In the WS-CRDS instrument, water is vaporized at controlled environment and transferred to an optical cavity by nitrogen carrier gas, and stable isotopic compositions of water vapor are measured using the degree of absorbance of specific wavelengths and the ratios of attenuation time of the laser intensity with the sensitivity of ppb to tens of ppt level. In this study, we introduce the principle of the WS-CRDS technology and the performance results including stability and comparisons with Isotope Ratio Mass Spectrometry (IRMS) and suggest possible applications of various topics in isotope hydrology.

Recent Technological Advances in Optical Instruments and Future Applications for in Situ Stable Isotope Analysis of CH4 in the Surface Ocean and Marine Atmosphere (표층해수 내 용존 메탄 탄소동위원소 실시간 측정을 위한 광학기기의 개발 및 활용 전망)

  • PARK, MI-KYUNG;PARK, SUNYOUNG
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.23 no.1
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    • pp.32-48
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    • 2018
  • The mechanisms of $CH_4$ uptake into and release from the ocean are not well understood due mainly to complexity of the biogeochemical cycle and to lack of regional-scale and/or process-scale observations in the marine boundary layers. Without complete understanding of oceanic mechanisms to control the carbon balance and cycles on a various spatial and temporal scales, however, it is difficult to predict future perturbation of oceanic carbon levels and its influence on the global and regional climates. High frequency, high precision continuous measurements for carbon isotopic compositions from dissolved $CH_4$ in the surface ocean and marine atmosphere can provide additional information about the flux pathways and production/consumption processes occurring in the boundary of two large reservoirs. This paper introduces recent advances on optical instruments for real time $CH_4$ isotope analysis to diagnose potential applications for in situ, continuous measurements of carbon isotopic composition of dissolved $CH_4$. Commercially available, three laser absorption spectrometers - quantum cascade laser spectroscopy (QCLAS), off-axis integrated cavity output spectrometer (OA-ICOS), and cavity ring-down spectrometer (CRDS) are discussed in comparison with the conventional isotope ratio mass spectrometry (IRMS). Details of functioning and performance of a CRDS isotope instrument for atmospheric ${\delta}^{13}C-CH_4$ are also given, showing its capability to detect localized methane emission sources.