Development of an in situ Raman spectrometer for measurement of sediment pore water geochemistry in a high-pressure reaction cell

We have developed and tested a novel in situ Raman spectrometer for geochemical studies of marine sediment pore water at a high-pressure reaction cell. With the high-pressure reaction cell, we can simulate appropriate pressure and temperature of the deep ocean up to 2000 m depth with 1-25 °C temperature range. A novel pore water Raman probe has been installed inside the high-pressure reaction cell, allows detailed measurement of the dissolved CH₄, SO₄^2-, H₂S, and pH inside the sediment pore water. Our particular interest for this device is to study the sediment pore water geochemistry change during the formation of the natural gas hydrate.