I have not achieved separation of cis and trans fatty acids derivatized as trimethylsilyl esters using N,O -BSTFA on the DB-5 Column, but I prefer this derivatization method as it is rather straightforward. I would like to get a high polarity column for my separation of cis and trans isomers and would like to know if anyone has tried using these columns for analyzing fatty acids derivatized as trimethyl silyl (TMS) esters and if possible, what column is recommended. Thank you