CHROMATOGRAPHIC CHARACTERIZATION OF ADSORBENTS FOR SELECTIVE SAMPLINGOF ORGANIC AIR-POLLUTANTS

Seven adsorption materials of various kinds were investigated by inver se gas chromatography. For 25 different organic compounds, specific re tention volume (V-g) and adsorption enthalpy (Delta H) with these adso rbents were calculated. According to the measured adsorbent retention ability, the materials can be characterized as follows. Amberlite XAD- 4 (styrene-divinyl-benzene-copolymer) and Porapak R (N-vinyl pyrrolidi ne-polymer) were found to be useful for sampling polar and nonpolar lo w-volatility compounds, whereas Amberlite XAD-8 (methacrylic acid-poly mer) retained only polar high-melting substances. Quantitative samplin g of high-melting nonpolar pollutants was possible with Tenax GC (2,6- diphenyi-p-phenyienoxide-polymer). The retention ability of these poly mers for volatile compounds such as methylene chloride was very small, hence quantitative collection was impossible. Polar highly volatile c ompounds can be adsorbed on silica gel, with preference to a modified version for amines. Activated charcoal was the only investigated adsor bent suitable for the efficient sampling of nonpolar highly volatile p ollutants.