Quantification of long-chain aldehydes by gas chromatography coupled to mass spectrometry as a tool for simultaneous measurement of plasmalogens and their aldehydic breakdown products

The cleavage of the specific vinyl ether linkage at the sn-1 position of pl asmalogens leads to the formation of two products: the 1-lyso-2-acyl glycer ophospholipid and a long-chain fatty aldehyde, Plasmalogens are measured by quantifying one of these two products. In this paper, we describe a rapid and sensitive procedure for measuring plasmalogens via quantification of lo ng-chain fatty aldehydes. After lipid extraction, the sn-1 vinyl ether bond of plasmalogens is cleaved by acidic hydrolysis. The produced aldehydes ar e then derivatized with (pentafluorobenzyl)hydroxylamine hydrochloride and analyzed by gas chromatography/mass spectrometry in selected-ion mode. Plas malogens are then indirectly quantified by subtracting the free aldehydes o btained without prior HCl treatment from the total aldehydes obtained after acidic hydrolysis. This method is applied to three rat brain areas selecte d for this study. Two of these are affected in neurodegenerative diseases ( cerebral cortex and hippocampus) and one is rich in white matter (cerebellu m). In comparison to other procedures, the advantages of this method are no t only its usefulness in plasmalogen quantification but also the identifica tion of aldehydic breakdown products. (C) 2000 Academic Press.