It is likely that there will be no effect, but the only way to be sure is to do the comparison yourself under your conditions with your chemicals and equipment.

Hi!. Storage in ethanol could cause some esterification with free fatty acids to produce ethyl esters. You could check if this has happened just running a TLC. The presence of ethyl esters could indicate you the reaction took place. In the future I would use chloroform better than ethanol for sample storage.

I agree with Joaquin. The liver has FAEE synthase that makes that fatty acids reacts with ethanol to form FAEE.

Were they stored at room temperature? I

Thank everybody for the useful answers.

Dear Louise A. Copeman, at the moment I do not now but I've already asked for this information. In the meantime, can you explain how the temperature can influence the above-mentioned reactions? thanks

I have never heard of preserving lipids in ethanol. I'm not a chemist so I'm not the best person to answer this question. However, storing lipids at warm temperatures and exposed to oxygen accelerates the hydrolysis and oxidation processes. Hydrolysis results in high free fatty acids that break off the glycerol backbones of phospholipids and triacylglycerols. Oxidation results in the breakdown of PUFA double bonds.