Detection of trace organic compounds by Stir Bar Sorptive Extraction: application to the evolution of the organic composition of hydrothermal fluids from the Rainbow site (36°N, Mid-Atlantic Ridge) over 3 years
(English)Manuscript (preprint) (Other academic)
The question of the abiogenic oil has been discussed and hydrothermal reactions have been suggested to abiotically generate hydrocarbons. Besides, ultramafic-hosted hydrothermal systems have been regarded as favourable environment for the emergence of life. Therefore, it is of great importance to investigate the presence of organic compounds in hydrothermal fluids. However, because of the sampling difficulties, the complexity of the matrix, the numerous interferences and the assumed trace level concentrations; it was considered a real challenge. Here we show that Stir Bar Sorptive Extraction (SBSE) coupled to Thermal Desorption – Gas Chromatography – Mass Spectrometry (TD-GC-MS) can be successfully applied to analyses of volatile and semi-volatile organic compounds in hydrothermal fluids. The method exhibited excellent reproducibility and conditioned samples appeared to be really stable for up to 3 years. This innovative and versatile technique was used to study the fluids from the ultramafic-hosted hydrothermal field Rainbow located at 36°14’N on the Mid-Atlantic Ridge (MAR). Despite relative stability for mineral composition and gas content is observed, analyses of fluids samples from 2005, 2007 and 2008 revealed more distinct organic compositions. In addition, results suggest the similarity of the organic content of the fluids regardless of the sampling location within the field, which may indicates the presence of a single reaction zone and that no further chemical reactions occur while fluids are transported to the seafloor.
SBSE, organic compounds, hydrothermal, ultramafic, MAR, serpentinisation
Earth and Related Environmental Sciences Analytical Chemistry Geochemistry
Research subject Geochemistry
IdentifiersURN: urn:nbn:se:su:diva-29192OAI: oai:DiVA.org:su-29192DiVA: diva2:231454