|Comparison of extraction and work up techniques for analysis of core and intact polar tetraether lipids from sedimentary environments
Lengger, S.K.; Hopmans, E.C.; Sinninghe Damsté, J.S.; Schouten, S. (2012). Comparison of extraction and work up techniques for analysis of core and intact polar tetraether lipids from sedimentary environments. Org. Geochem. 47: 34-40. dx.doi.org/10.1016/j.orggeochem.2012.02.009
In: Organic Geochemistry. Elsevier: Oxford; New York. ISSN 0146-6380; e-ISSN 1873-5290, meer
- Lengger, S.K., meer
- Hopmans, E.C., meer
- Sinninghe Damsté, J.S., meer
- Schouten, S., meer
Glycerol dibiphytanyl glycerol tetraether-based intact polar lipids (IPL GDGTs) are used as biomarkers for living Archaea and are analyzed utilizing a variety of extraction and quantification techniques. Most IPL GDGT studies have used a modified Bligh-Dyer extraction method, but it has been suggested that Soxhlet extraction may be more efficient for environmental samples and biomass. We investigated the impact of three different extractions (Soxhlet, Bligh-Dyer and accelerated solvent extraction, ASE), two IPL quantification methods and two work up techniques (Na2SO4 and SiO2 column) on the amount and distribution of CL (core lipid)- and IPL-derived GDGTs and crenarchaeol-based IPLs in marine sediments from the Arabian Sea and Icelandic shelf, as well as a microbial mat from a Dutch beach. The different extraction procedures gave a similar yield of CL- and IPL-derived GDGTs. Direct analysis of crenarchaeol IPLs showed, however, that, while GDGTs with a monohexose head group were not affected by the extraction method, there was a large effect on IPL GDGTs containing dihexose or hexose, phosphohexose head groups. Quantification of IPL-derived GDGTs by way of either separation over a silica column or by subtraction of CL GDGTs in the total lipid extract before and after hydrolysis gave similar results, but the 'subtraction-method' had a relatively large quantification error. However, the silica column, as well as drying over a Na2SO4 column, resulted in a loss of the hexose, phosphohexose IPLs by up to 80%. Based on the results, a modified Bligh-Dyer extraction with as little further treatment as possible is recommended to allow measurement of the full range of IPL GDGTs in sediments.