DETERMINATION OF ALDEHYDES AND OTHER LIPID-PEROXIDATION PRODUCTS IN BIOLOGICAL SAMPLES BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The extremely broad spectrum of the biological effects of aldehydic li pid peroxidation products has necessitated the development of a techni que that can quantitate all of the aldehydes formed in biological mate rials. The proposed method is based on the use of O-(2, 3, 4, 5, 6-pen tafluorobenzyl) hydroxylamine hydrochloride (PFBHA . HCl) to form the O-pentafluorobenzyl-oxime (PFB-oxime) derivatives of 22 saturated and unsaturated aldehydes (C-2-C-12) including hexanal, 4-hydroxy-non-2-en al (HNE), and malondialdehyde (MDA), followed by trimethylsilylation o f the hydroxyl group to trimethylsilyl (TMS) ethers. The PFB-oxime-TMS derivatives were analyzed by capillary column gas chromatography-nega tive-ion chemical ionization mass spectrometry (GC-NICIMS) with ammoni a as reagent gas. Quantitation was achieved using benzaldehyde-ring-D- 5 as an internal standard in selected ion recording (SIR) mode. Standa rd curves were Linear (r > 0.99) for all individual aldehydes. The det ection Limit was between 50 and 100 fmol per 1 mu l injected aldehyde. Recovery of all aldehydes from urine, plasma, and tissue homogenate w as over 85%, except HNE, trans-2-octenal and trans-2,-cis-6-nonadienal from plasma and tissue sample, which were between 60 and 80%, suggest ing these aldehydes may bind to protein and Lipid components, especial ly to SH groups of proteins. The high sensitivity of this method allow s the measurement of physiological aldehyde levels in biological sampl es. The products of aldehyde metabolism can also be measured by this a ssay. (C) 1995 Academic Press, Inc.