Raman vibrational spectral characteristics and quantitative analysis of H₂ up to 400°C and 40 MPa

Abstract

In situ Raman detection is an ideal method to determine the concentration of dissolved H 2 in deep-sea high temperature hydrothermal fluids, but studies on in situ Raman qualitative and quantitative analyses of H 2 that are suitable for detection in high temperature hydrothermal fluids are lacking. In this study, the Raman characteristics of gaseous and dissolved H 2 were researched at 0-400°C and 0-40 MPa in detail, which cover most deep-sea hydrothermal environments. The strong density and temperature dependences of the wavenumber and bandwidth of gaseous hydrogen vibrational Raman bands were observed. The interactions between the water molecules and hydrogen molecules were affected by temperature and pressure, and the opposite effect on the vibrational band of dissolved hydrogen was observed before and after reaching the critical condition of water. A high temperature and pressure quantitative analysis model suitable for in situ Raman detection of dissolved H 2 was also developed with the linear equation A H 2 ð Þ=A H 2 O ð Þ¼1:437 or 1:262 ð Þ ×C H 2 ð Þ, where A (H 2 )/A (H 2 O) is the peak area ratio of H 2 and H 2 O, and C (H 2 ) is the concentration of dissolved H 2 in mol/kg. The experimental temperature and pressure conditions did not influence the linear trend between the peak area ratio of A (H 2 )/A (H 2 O) and the concentrations of H 2 , which indicated that the calibration model can be applied to high temperature and pressure environments. KEYWORDS deep-sea, hydrogen, hydrothermal vent fluid, in situ, quantitative analysis ---This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

In situ Raman quantitative detection of methane concentrations in deep‐sea high‐temperature hydrothermal vent fluids

“…The spectral range (100–4,325 cm −1 ) was split into two regions (100–2,100 and 2,100–4,325 cm −1 ) on the surface of the CCD; therefore, the spectral resolution of the RiP system was approximately 1 cm −1 . [ 21,31 ] Before each deployment, the wavenumber and intensity calibration of the RiP system were processed by neon and halogen lamps.…”

“…In addition, the instruments and optical paths used can impact the relationship between spectral intensity and methane concentration. [ 30,31 ] Therefore, a new CH 4 quantitative calibration model suitable for a deep‐sea Raman system needs to be developed to accurately determine the concentration of methane in hydrothermal fluids from in situ Raman spectra.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Lamadrid and colleagues described a relationship between Raman spectral features and fugacity in mixtures of gases . Li et al reported vibrational Raman spectral characteristics and quantitative analysis of H 2 up to 400°C and 40 MPa . Liu et al studied the unravelling of the decomposition products of phosphine under high pressure where it shows superconducting behaviour .…”

“…[189] Li et al reported vibrational Raman spectral characteristics and quantitative analysis of H 2 up to 400°C and 40 MPa. [190] Liu et al studied the unravelling of the decomposition products of phosphine under high pressure where it shows superconducting behaviour. [191] Maczka and co-workers described Raman scattering of pressureinduced phase transitions in perovskite-like acetamidninium manganese formate.…”

Method for extracting Raman spectra characteristic variables of biological sample based on Hilbert–Huang transform

“…Therefore, the characteristic peak assignment, including peaks locating and peak's intensity measuring, is a simple and effective characteristic‐variables‐extracting method . For a longtime study, peaks assignment derives some other feature extraction methods such as half‐spectrum peak width measurement, peak area measurement, peak‐to‐peak line slope measurement, and peak‐to‐peak height ratio measurement . However, compared with mass spectrometry and infrared spectroscopy, Raman spectroscopy has a shorter history.…”