Abstract A method is described for simultaneous extraction and chromatographic separation of saturated hydrocarbons (n-alkanes) and unsaturated long-chain ketones (alkenones) from glycerol dialkyl glycerol tetraethers (GDGTs) using selective accelerated solvent extraction (ASE). We show that the method can be used to successfully separate n-alkanes and alkenones from GDGTs in marine sediment samples and n-alkanes from GDGTs in lake sediments and soil samples. A comparison of our method with analysis of samples purified using classical silica column chromatography demonstrates that the new method does not affect the alkenone unsaturation index ( U 37 K' ), the TetraEther indeX (TEX86), the Methane Index (MI), the Ring Index (RI), the branched-GDGT-based paleotemperature and soil pH indices, the Branched and Isoprenoid Tetraether (BIT) index, the n-alkane average chain length (ACL) or the carbon preference index (CPI). The new procedure results in higher sample recoveries for n-alkanes and more precise U 37 K' estimates at low concentrations, and contributes to reduced analyst laboratory time.

中文翻译：

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通过选择性加速溶剂萃取从甘油二烷基甘油四醚中同时萃取和色谱分离正烷烃和烯酮

摘要 描述了一种使用选择性加速溶剂萃取 (ASE) 从甘油二烷基甘油四醚 (GDGT) 中同时萃取和色谱分离饱和烃（正烷烃）和不饱和长链酮（烯酮）的方法。我们表明该方法可用于成功地从海洋沉积物样品中的 GDGT 中分离正烷烃和烯酮，以及从湖泊沉积物和土壤样品中的 GDGT 中分离正烷烃。我们的方法与使用经典硅胶柱色谱纯化的样品分析的比较表明，新方法不影响烯酮不饱和指数 (U 37 K' )、四醚指数 (TEX86)、甲烷指数 (MI)、环指数 (RI)、基于支链 GDGT 的古温度和土壤 pH 指数、支链和类异戊二烯四醚 (BIT) 指数，正构烷烃平均链长 (ACL) 或碳偏好指数 (CPI)。新程序可提高正构烷烃的样品回收率，并在低浓度下获得更精确的 U 37 K' 估计值，并有助于缩短分析实验室时间。