High Uptake Rate Radial Diffusive Sampler Suitable for Both Solvent and Thermal Desorption

A new diffusive sampler with radically changed diffusive path geometry was developed. The small cylinder has a height greater than its radius; the diffusive surface is the external cylindrical one, and the adsorber is a coaxial inner cylindrical cartridge. Due to the high value of diffusive area-path length ratio and to the high loading capacity of the adsorber (up to 80 mg for ethyl acetate), this original geometry allows high and constant sampling rates in a wide range of concentrations and exposure times. The cylindrical shape of the cartridge enables both thermal and solvent desorbing as well as active sampling. Using activated charcoal, exposure time can range from 30 minutes to 24 hours, thus allowing monitoring both in the workplace and in the outdoor environment. As an example, the 80 cm3/min uptake rate of benzene assures a detection limit as low as 2 µg/m3 after 24-hour exposure time. The uptake rate for 32 organics was measured experimentally, and results were found to be highly reproducible an...