Ambient Volatile Organic Compound Monitoring by Diffusive Sampling. Compatibility of High Uptake Rate Samplers With Thermal Desorption†

Abstract

Field and laboratory validation studies were carried out on a novel, high uptake rate, radial diffusive sampler loaded with Carbotrap, a thermally desorbable adsorbent. For field experiments parallel techniques were employed for comparison. The goal was to assess the compatibility of the device for subsequent thermal desorption and preconcentration of the sample for analysis. Some unexpected results were obtained especially for benzene, where it was observed that, under certain conditions the longer the device was exposed to an atmosphere, the less sample was collected. A possible explanation for these results is put forward by applying knowledge previously acquired on saturation and competitivity effects. An alteration to the sampler geometry is proposed which, through further laboratory and field work, is shown to overcome this problem.