• archaeal tetraether lipid

In the last decade, a new biomarker paleotemperature approach based on the relative abundances of glycerol dialkyl glycerol tetraethers (GDGTs) has been developed that complements and extends the capabilities of the alkenone proxy. GDGTs are relatively large (up to 86 carbon atoms) membrane lipids produced by Archaea and some Bacteria. They are common, typically abundant, easy-to-analyze lipids found in a variety of environments. Such attributes make GDGTs a promising universal tool for estimating temperatures in the geologic past, especially in deep geologic time.
In this work, a method to increase the detection of GDGTs to allow a better screening of the lipid cores based on the Steglich esterification reaction has been explored.
The following thesis concerns the efficiency of the derivatization approach. The esterification was tested first on a model lipid, then on various molecules with different structure, such as sterols, diols and also a composed mixture. The derivatization reaction had been tested on a medium polar fraction sample taken from a natural loam soil and analysed by liquid chromatography-mass spectrometry.