AMBIENT VOLATILE ORGANIC-COMPOUND MONITORING BY DIFFUSIVE SAMPLING - COMPATIBILITY OF HIGH UPTAKE RATE SAMPLERS WITH THERMAL-DESORPTION

Field and laboratory validation studies mere carried out on a novel, h igh uptake rate, radial diffusive sampler loaded with Carbotrap, a the rmally desorbable adsorbent, For field experiments parallel techniques mere employed for comparison, The goal was to assess the compatibilit y of the device for subsequent thermal desorption and preconcentration of the sample for analysis, Some unexpected results were obtained esp ecially for benzene, where it was observed that, under certain conditi ons the longer the device was exposed to an atmosphere, the less sampl e was collected, A possible explanation for these results is put forwa rd by applying knowledge previously acquired on saturation and competi tivity effects, An alteration to the sampler geometry is proposed whic h, through further laboratory and field work, is shown to overcome thi s problem.