Epicuticular waxes from vascular plants and particles in the lower troposphere: Analysis of lipid classes by Iatroscan thin-layer chromatography with flame ionization detection

Abstract

The neutral lipids in a variety of samples of acrosol particulate matter, representative source vegetation, and soil have been analyzed by Iatroscan thin-layer chromatography (TLC) with flame ionization detection (FID). Iatroscan, combining the separation capabilities of TLC on silica 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 collection of rural atmospheric particles, epicuticular waxes from possible source vegetation, and soil, covering four geographic regions in a transect across the State of Oregon, U.S.A. Aerosol particles, epicuticular waxes of representative vegetation species, and surface soil contain large amounts of unknown polar material, with similar amounts of neutral lipids including hydrocarbons, carboxylic acids, ketones (aldehydes), wax esters (generally not detectable in the aerosols), and alcohols. The distributions of the lipid classes in the epicuticular waxes of the vegetation vary a great deal from species to species. The distribution 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 permitted a general correlation between the source vegetation and the corresponding aerosol particles. This is the first description of a rapid single scan method for the separation and analysis of extractable organic matter from aerosol particles and vegetation using the latroscan TLC with FID.