ABSTRAK
Complex air sample extracts were prefractionated on acidic- and basic-buffered silica. Compound overlap between acidic and basic polar substance (e.g. substituted polycylyc aromatic hydrocarbons) was greatly reduced, facilitating identification by gas chromatography-mass spectrometry. Furthermore, additional information on compound acidity and polarity is obtained, which helps to characterize compounds with identical electron-impact mass spectra but different structures.