Editing Fatty acid (section)

==Analysis==

The chemical analysis of fatty acids in lipids typically begins with an [[interesterification]] step that breaks down their original esters (triglycerides, waxes, phospholipids etc.) and converts them to [[methyl]] esters, which are then separated by gas chromatography<ref>{{cite journal | vauthors = Aizpurua-Olaizola O, Ormazabal M, Vallejo A, Olivares M, Navarro P, Etxebarria N, Usobiaga A | display-authors = 6 | title = Optimization of supercritical fluid consecutive extractions of fatty acids and polyphenols from Vitis vinifera grape wastes | journal = Journal of Food Science | volume = 80 | issue = 1 | pages = E101-7 | date = January 2015 | pmid = 25471637 | doi = 10.1111/1750-3841.12715 }}</ref> or analyzed by [[gas chromatography]] and mid-[[infrared spectroscopy]].

Separation of unsaturated isomers is possible by [[Argentation chromatography|silver ion complemented thin-layer chromatography]].<ref>{{Cite journal | doi = 10.1093/chromsci/25.7.302| pmid = 3611285| title = Separation of Fatty Acids or Methyl Esters Including Positional and Geometric Isomers by Alumina Argentation Thin-Layer Chromatography| journal = Journal of Chromatographic Science| volume = 25| issue = 7| pages = 302–6| year = 1987| last1 = Breuer | first1 = B.| last2 = Stuhlfauth | first2 = T.| last3 = Fock | first3 = H. P.}}</ref> Other separation techniques include [[high-performance liquid chromatography]] (with short columns packed with [[silica gel]] with bonded phenylsulfonic acid groups whose hydrogen atoms have been exchanged for silver ions). The role of silver lies in its ability to form complexes with unsaturated compounds.