Characterization of Hydroxy and Hydroperoxy Polyunsaturated Fatty Acids by Mass Spectrometry.

Lipids containing unsaturated doubles bonds are oxidized by enzymatic and non-enzymatic mechanisms yielding hydroperoxides and hydroxides as primary products.This process has been implicated in physiological and pathological mechanisms. Thus, precise characterization and quantification of lipid oxidation products in biological samples can provide important mechanistic insights. In this context, the use of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to characterize the primary products of polyunsaturated fatty acids, like hydroxides and hydroperoxides, is a sensitive, specific and versatile tool. Here we will focus on the characterization and specific analysis of hydroxy and hydroperoxy regioisomers of linoleic acid, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid by LC-MS/MS.