I was going to extract the lipid from shark tissue in order to run stable isotope analysis. I do not know if the extracted lipids will still be useful for your analysis after removal because they are not of interest to me.

Maybe you can find something on a viable method for ethanol samples by looking at papers about stable isotopes.

This could help you: Methods to collect, preserve, and prepare elasmobranch tissues for stable isotope analysis; Kim and Koch; 2012

Agreed - ethanol denatures lipids by breaking the hydrogen bonds which leads to issues with extraction and quantification. Analysis on fresh tissue is ideal, then, nitrogen freezing or storage  -80C for

I think an issue would be that the ethanol might extract some lipids, mainly triacylglycerol. You also have the issue that if ethanol is present during methylation (to form fatty acid methyl esters) you could also make ethyl esters which would mess up your analyses.

You may have different options based on sample size and sample to ethanol ratio. You could draw off the ethanol, dry it and add residue back to the whole sample. You could also freeze dry samples to remove ethanol from samples, and then do lipid extraction/methylation, or direct methylate...

I'm also assuming you are interested in fatty acids and not lipid classes

Hi,

I know the topic is old but in case someone is interested the authors of this paper did fatty acid analyses on samples from ethanol. It is not discussed how this can affect the results though

https://www.mdpi.com/1422-0067/14/4/7048/htm