||Konn Cecile1, 2, Charlou Jean-Luc1, Donval Jean-Pierre1, Holm Nils G.2
||1 : IFREMER, Ctr Brest, Lab Geochim Metallogenie, UR Geosci Marines, F-29280 Plouzane, France.
2 : Stockholm Univ, Geochem Sect, Dept Geol Sci, S-10691 Stockholm, Sweden.
||Geochemical Transactions (1467-4866) (Biomed Central Ltd), 2012-11 , Vol. 13 , N. 8 , P. 1-19
|WOS© Times Cited
||Sample preparation, Extraction, Organic compounds, Hydrothermal fluids, Ultramafic rocks
||The analysis of the dissolved organic fraction of hydrothermal fluids has been considered a real challenge due to sampling difficulties, complexity of the matrix, numerous interferences and the assumed ppb concentration levels. The present study shows, in a qualitative approach, that Stir Bar Sorptive Extraction (SBSE) followed by Thermal Desorption - Gas Chromatography - Mass Spectrometry (TD-GC-MS) is suitable for extraction of small sample volumes and detection of a wide range of volatile and semivolatile organic compounds dissolved in hydrothermal fluids. In a case study, the technique was successfully applied to fluids from the Rainbow ultramafic-hosted hydrothermal field located at 36 degrees 14'N on the Mid-Atlantic Ridge (MAR). We show that n-alkanes, mono-and poly-aromatic hydrocarbons as well as fatty acids can be easily identified and their retention times determined. Our results demonstrate the excellent repeatability of the method as well as the possibility of storing stir bars for at least three years without significant changes in the composition of the recovered organic matter. A preliminary comparative investigation of the organic composition of the Rainbow fluids showed the great potential of the method to be used for assessing intrafield variations and carrying out time series studies. All together our results demonstrate that SBSE-TD-GC-MS analyses of hydrothermal fluids will make important contributions to the understanding of geochemical processes, geomicrobiological interactions and formation of mineral deposits.
|Publisher's official version