I'm running lipid extraction on several animal tissue samples for future isotope analysis. I know the Folch method of extraction is widely used and accepted as the "gold standard" in my scenario, however, I'm concerned that the addition of water in the extraction will contaminate my sample tissue (my goal is to look at the hydrogen isotope ratios of purified lipids in animal sample). I'm trying to better understand the reactions that take place during this extraction to see if H from the water has any chance of replacing H in my tissue sample (thus altering the isotopic signature). Alternatively, I see some papers that have modified the Folch method to exclude the addition of water, any rely solely on chloroform:methanol for the extraction. Is there a risk that some lipids will not dissociate from proteins or carbs and get excluded from the pure lipid extract if water is not used as solvent?
Hi dear Madelyn
in fact, there is another better method such as "Bligh and Dyer", which I used that, for extracting lipids. you can check this article to get more info.
My regards
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Thank you, Paul Van Veldhoven That is very helpful.
I am still curious about the molecular interactions that occur (if any) to disrupt the interaction between lipid-lipid and lipid-protein. Aside from introducing water in my extraction, my other concern is that methanol also contains H, and therefore has the potential to replace deuterium in my sample (thus biasing the hydrogen isotope ratio I am trying to measure). Is there a resource you can recommend that explains how lipids become dissociated during extraction (i.e. what does "disrupting the hydrophobic interactions" entail)?
Hi Madelyn, the method is gentle and will only exchange the exchangeable hydrogens (which can also exchange with vapour in the air). It depends on what measurements you want to use how to deal with this. For compound specific H Isotopes, you need to derivatise the exchangeable H. For bulk, you would equilibrate with two different waters of known values.
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