Efficiency of passive sampling by adsorbents

The efficiency of passive samplers can be influenced strongly by the adsorption isotherm. In this study calculations of sampling efficiency were made in terms of dimensionless variables for adsorption controlled by the Langmuir, Freundlich, and Dubinin-Radushkevich isotherms, respectively. Of particular importance is that for the latter isotherm, which is often followed by activated charcoal for the adsorption of solvent vapors, passive sampling may remain highly efficient until a significant fraction of the capacity of the adsorbent has been utilized.