Title: Analysis of unsaturated compounds by Ag+ coordination ionspray mass spectrometry: studies of the formation of the Ag+/lipid complex.

Authors: Seal, Jennifer R; Havrilla, Christine M; Porter, Ned A; Hachey, David L

Published In J Am Soc Mass Spectrom, (2003 Aug)

Abstract: Coordination ionspray mass spectrometry (CIS-MS) is a useful tool in the detection and identification of cholesterol ester and phospholipid hydroperoxides and diacyl peroxides. Extensive studies of a series of cholesterol esters using CIS-MS revealed the following: (1) Cholesterol esters with equal number of double bonds as the internal standard showed a linear relative response in the mass spectrometer while compounds with non-equal numbers of double bonds gave a nonlinear relative response. (2) Complex adducts containing cholesterol ester, silver ion, AgF, AgBF(4), and 2-propanoxide form when silver is in molar excess of cholesterol esters, reducing the [M + Ag](+) signal. (3) In a mixture of cholesterol esters where silver is limiting, Ch22:6 and Ch20:4 bind to silver at the expense of Ch18:2 and have a higher signal in the mass spectrometer. (4) In a mixture of cholesterol esters where silver concentration is twofold greater than total cholesterol ester concentration, Ch22:6 and Ch20:4 form large complex adducts more frequently than Ch18:2 and have a lower signal in the mass spectrometer.

PubMed ID: 12892911

MeSH Terms: Cations, Monovalent/chemistry*; Cholesterol Esters/analysis; Cholesterol Esters/chemistry; Fats, Unsaturated/analysis; Fats, Unsaturated/chemistry*; Lipid Peroxidation; Silver/chemistry*; Spectrometry, Mass, Electrospray Ionization/methods*