Novel SERS Probe Based on Ag Nanobean/Cu Foam for Deep-Sea Extreme Environment Biomolecule Detection.

Here, we report on progress made in coupling advances in surface-enhanced Raman scattering (SERS) techniques with a deep-ocean deployable Raman spectrometer. Our SERS capability is provided by development of a Cu foam-loaded silver-nanobean (Ag/Cu foam) which we have successfully coupled to the tip of a Raman probe head capable of insertion into deep-sea sediments and associated fluids. Our purpose is to expand the range of molecular species which can be detected in deep-sea biogeochemical environments, and our initial targets are a series of amino acids reportedly found in pore waters of seep locations.

Comparison of Raman spectral characteristics and quantitative methods between CH and CH from 25 to 400 °C and 50 to 400 bar.

In recent years, increasing attention has been given to quantifying the isotopic compositions of gases by Raman spectroscopy. However, related research on the carbon isotopes of CH is still lacking. In this study, the Raman spectral characteristics of CH and CH in the pure CH system and in the CH-HO system are comprehensively studied at temperatures ranging from 25 to 400 °C and pressures ranging from 50 to 400 bar.

Raman quantitative monitoring of methanogenesis: Culture experiments of a deep-sea cold seep methanogenic archaeon.

Gas production from several metabolic pathways is a necessary process that accompanies the growth and central metabolism of some microorganisms. However, accurate and rapid nondestructive detection of gas production is still challenging. To this end, gas chromatography (GC) is primarily used, which requires sampling and sample preparation.

Raman spectral characteristics of CO/CO and quantitative measurements of carbon isotopic compositions from 50 to 450 °C and 50 to 400 bar.

The carbon isotopic composition of CO is traced to its different origins and widely used in the fields of geology, biology, and chemistry. Raman spectroscopy can be performed in situ, is nondestructive, and requires no sample preparation; these characteristics enable Raman spectroscopy to be considered a new alternative method to measure the carbon isotopic composition of CO. In this work, Raman spectra of high-purity CO, CO, and six CO-CO binary mixtures with known mixing ratios were collected using a High Pressure Optical Cell (HPOC) at 50-450 °C and 50-400 bar.

A Piecewise Model for In Situ Raman Measurement of the Chlorinity of Deep-Sea High-Temperature Hydrothermal Fluids.

The chlorinity of deep-sea hydrothermal fluids, representing one of the crucial deep-sea hydrothermal indicators, indicates the degree of deep phase separation of hydrothermal fluids and water/rock reactions. However, accurately measuring the chlorinity of high-temperature hydrothermal fluids is still a significant challenge. In this paper, a piecewise chlorinity model to measure the chlorinity of high-temperature hydrothermal fluids was developed based on the OH stretching band of water, exhibiting an accuracy of 96.

Discovery of supercritical carbon dioxide in a hydrothermal system.

Supercritical CO appearing as bubbles in hydrothermal vents was identified in the south part of the Okinawa Trough using in situ Raman spectroscopy. Significantly, the N peak in supercritical CO is much larger than those in seawater and vent fluids, indicating that supercritical CO enriches N from the surrounding environment. Considering that the partial pressures of CO and N in the Earth's proto-atmosphere were ~10-20 MPa, supercritical CO with high N was likely the dominant CO phase near the water-air interface in the early history of the Earth, which promoted the synthesis, pre-enrichment and preservation of amino acids and other organic matters that are essential to the origin of life.

A New Approach to Measuring the Temperature of Fluids Reaching 300 ℃ and 2 mol/kg NaCl Based on the Raman Shift of Water.

The OH stretching band of water is very sensitive to temperature and salinity for the existence of hydrogen bonds between HO molecules. In this study, the OH stretching band was deconvoluted into two Gaussian peaks, with peak 1 at approximately 3450 cm and peak 2 at approximately 3200 cm. The positions of peaks 1 and 2 both shifted to higher wavenumbers with increasing temperature from 50 ℃ to 300 ℃.

A Direct Quantitative Raman Method for the Measurement of Dissolved Bisulfate in Acid-Sulfate Fluids.

Raman spectroscopy has been applied to the quantitative analysis of the concentration of bisulfate in acid-sulfate fluids at different temperatures. The quantitative analysis method is based on the peak area ratios of [Formula: see text](ν) and HO (ν), where PA([Formula: see text]/HO) = [[Formula: see text]] × (0.0066 × T + 1.

In Situ Raman Spectral Characteristics of Carbon Dioxide in a Deep-Sea Simulator of Extreme Environments Reaching 300 ℃ and 30 MPa.

Deep-sea carbon dioxide (CO) plays a significant role in the global carbon cycle and directly affects the living environment of marine organisms. In situ Raman detection technology is an effective approach to study the behavior of deep-sea CO. However, the Raman spectral characteristics of CO can be affected by the environment, thus restricting the phase identification and quantitative analysis of CO.