Performance of a thermally desorbable type-tube diffusive sampler for verylow air concentrations monitoring

Perkin-Elmer tubes packed with Tenax TA have been tested for the monitoring of low concentrations of aromatic compounds and linear alkanes using diffu sive sampling. The uptake rates have been investigated for different exposu re doses. A particular hexane and benzene behaviour has been observed: thei r uptake rates decrease rapidly in the lower exposure doses and so follow a n exponential curve. The uptake rates of heavier compounds adopt another te ndency: a slow decrease with time following a linear profile. The relative humidity influence has been studied too, and no water perturbation has been recorded. (C) 1999 Elsevier Science Ltd. All rights reserved.