Characterization and quantification of human plasma lipids from crude lipid extracts by field desorption mass...

The main classes of human plasma lipids, free fatty acids, cholesterol, cholesterol esters, triglycerides and phosphatidylcholines were identified and quantified from samples of human plasma by field desorption mass spectrometry. A crude lipid extract was prepared from 50 microliters of human plasma and a 1-5% aliquot thereof was subjected directly to field desorption mass spectrometry without any chromatographic separation of the extract constituents. Within the classes of free fatty acids, triglycerides and phosphatidylcholines the fatty acid profile was obtained directly from the mass spectrum and accurate quantification could be achieved by the addition of stable isotope labelled internal standards.