Retention behaviour of volatile C1–C3 fluoroalkanes upon selected preconcentration adsorbents: I. Carbon molecular sieves and activated charcoals

The retention behaviour of several gaseous fluorinated greenhouse gases on carbon-based adsorbents is presented. Retention, calculated on the basis of compound breakthrough volume (BTV), is dependent on the molecular composition of the adsorbate, with compounds possessing chlorine or polarisable hydrogens being better retained than those possessing higher fluorine content. Of the adsorbents tested the carbon molecular sieves (CMSs) of highest surface area show greater retention than those with lower area. Retention of fluorocarbons is generally higher on activated charcoals but this adsorbent type can cause irreversible retention, possible degradation and is more difficult to use practically due to its heterogeneous composition. These breakthrough volume results can be used to determine the best combination and quantities of each adsorbent that can be used within a preconcentration device with a view to developing an analytical system for the determination of fluorocarbon gases in low concentration air samples.