EPICUTICULAR WAXES FROM VASCULAR PLANTS AND PARTICLES IN THE LOWER TROPOSPHERE - ANALYSIS OF LIPID CLASSES BY IASTROSCAN THIN-LAYER CHROMATOGRAPHY WITH FLAME IONIZATION DETECTION

The neutral lipids in a variety of samples of aerosol particulate matt er, representative source vegetation, and soil have been analyzed by I atroscan thin-layer chromatography (TLC) with flame ionization detecti on (FID). Iatroscan, combining the separation capabilities of TLC on s ilica coated chromarods with semiquantitation by FID, provides a rapid and sensitive method for lipid analysis which is lacking in the other analytical procedures. Lipid classes were analyzed in extracts of a c ollection of rural atmospheric particles, epicuticular waxes from poss ible source vegetation, and soil, covering four geographic regions in a transect across the State of Oregon, U.S.A. Aerosol particles, epicu ticular waxes of representative vegetation species, and surface soil c ontain large amounts of unknown polar material, with similar amounts o f neutral lipids including hydrocarbons. carboxylic acids, ketones (al dehydes), wax esters (generally not detectable in the aerosols), and a lcohols. The distributions of the lipid classes in the epicuticular wa xes of the vegetation vary a great deal from species to species. The d istribution of the lipid classes in surface soil differs from those of the vegetation and aerosol particles. Comparison of the neutral lipid classes in the predominant vegetation waxes and the aerosols permitte d a general correlation between the source vegetation and the correspo nding aerosol particles. This is the first description of a rapid sing le scan method for the separation and analysis of extractable organic matter from aerosol particles and vegetation using the Iatroscan TLC w ith FID.