Use of C18 and silica-gel coated Sep-Pak cartridges for the determination of carbonyls in air by liquid chromatography Original Research Article

C18 and silica-gel cartridges coated with 2,4-dinitrophenylhydrazine (2,4-DNPH) were compared for the determination of formaldehyde, acetaldehyde, acetone, propionaldehyde and butyraldehyde levels from ambient air. Liquid chromatography (LC) was used for the analysis, and clear differences were found for acetone retention on each type of coated cartridge. Moreover, double peaks of acetaldehyde were observed in LC analysis from samples simultaneously collected in both impregnated C18 and silica-gel cartridges. By using a KI filter during sampling to avoid ozone interference, retention and analysis were improved for some relevant carbonyl compounds in air. 2,4-DNPH silica-gel cartridges were used to determine carbonyls in ambient air from `Centro de Investigaciones Energéticas, Medioambientales y Tecnológicasʹ (CIEMAT), located in Madrid surroundings.