The chromatographic separation properties of long, thin adsorption tubes enable substance-specific quantitative enrichment and reduction to be achieved when sampling and thermal desorption are carried out in the same flow direction.
The specific retention volumes, and also the breakthrough and peak end volumes, of 69 compounds in the boiling range between -1 64 and 126OCand of a relative molecular mass between 16 and 11 9 were determined at temperatures between 30 and 130OC: normal alkanes, isoalkanes, cycloalkanes, alkenes, polyenes, alkynes, aromatics, ethers, alcohols, aldehydes, ketones, carboxylic acids and their esters, nitroalkanes, O-heterocycles, S-heterocycles, chloroal kanes, water, nitrogen monoxide, nitrogen dioxide, carbon dioxide, and sulfur dioxide.
The correlation between adsorbent temperature and specific retentionvolumeof thesecomponents, presented in the form of diagrams, permits the required quantity of adsorbent to be determined for a given sample volume. Contrary to literature sources, even extremely volatile compounds such as propane, propene, methanol, formaldehyde, formic acid, and chloromethane can be quantitatively retained on Tenax provided the operating conditions are appropriately selected.