Solvent Challenges Associated with the Storing and Extraction of Lipids

Posted on February 07, 2019

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Mass spectrometry is a powerful tool for the quantification and identification of lipid species. However, low level contaminants present in solvents can interact with lipid species to form chemical variants leading to artifacts in lipid analysis. Additionally, lipid solutions may interact with various surfaces to produce altered compounds and extract contaminants adding an additional layer of complexity to lipid analysis. This associated blog and video highlights the importance of using high quality solvents and evaluating the best extraction method for lipidomic mass spectrometry analysis Read on to learn more, and make sure to check out our Tech Talk on Solvent Challenges Associated with the Storing and Extraction of Lipids.

Problems That Arise During Extraction of Lipids

Solvents are an important part of lipidomic studies. For organic extractions, you can tailor the extraction to optimize your yield of a certain class of lipids while minimizing interference from other classes of lipids that may be problematic to your study.

The other type of extractions that are possible for lipids, solid phase extractions, are used extensively to isolate lipids based on the hydrophobic character or lipophobic character compared to other biomolecules that are not retained by these substrates.

The Bligh/Dyer technique is a method of total lipid extraction and purification. By our studies, the Bligh/Dyer technique with Chloroform-Methanol-water allows you to recover triglycerides very well (91.8 percent yield) and yields excellent extraction of phospholipids. But if you change your immiscible solvent to an isooctane ethyl acetate mixture, you still get excellent recovery of the triglyceride (93.5 percent) but very poor recovery of the phospholipid.

So this is a way for you to use solvent reaction to simplify your next step by avoiding problems that would arise due to interfering compounds. Carefully devising your extraction can be a useful way to optimize an isolation protocol.

Problems That Arise During Handling and Storing of Solvents

At Avanti, we have compiled several factors that should be taken into account when storing solvents. First of all, all solvents contain trace amounts of contaminants, no matter which solvents you buy. And some of these contaminants can interact with the class of lipids that you’re studying, which you must be aware of. Be aware that your intuition about what constitutes the best solvent may not be right. For example, you may think that stabilizers add impurities and that you should avoid solvents that include them, but stabilizers are actually critically important.

Also, you always want to make sure to use fresh solvents. The problems that arise when using solvents often result from the method of storage and exposure to light. Chloroform is one great example of potential storage problems. This compound is used for lipid extractions by the Bligh/Dyer method, but it can undergo a decomposition reaction that is catalyzed by the presence of ultraviolet light and oxygen. This would form phosgene, a very reactive molecule. So, if you’re not careful with your chloroform, and if you don’t store it in bottles that are protected from light, phosgene has the potential to ruin your study. The most effective way to minimize these problems, though, is to use fresh solvents.

In Summary

Always think about what solvent system you’re using to extract lipids, because it can pay very big dividends to you in your final analysis. Also, pay attention to what solvents you’re using, how you’re storing them and what might cause undesired reactions within them.

Contact Avanti for more information on obtaining high-quality lipids or lipid standards for your research.