Preparation and characterisation of a planar pre-concentrator for benzene based on different activated carbon materials deposited by air-brushing

A high area planar pre-concentrator based on various microporous activated carbons of different origins, granularities and preparation conditions, is studied. The adsorbing layer of different thicknesses was deposited on a self-heated planar substrate using the air-brushing technique. By coupling the pre-concentrator to a mass spectrometer, the thermo-desorption of benzene induced by application of a heat pulse was monitored with time. The effects of adsorbent layer thickness, grain size, origin, and activation conditions on the adsorption capacity and pre-concentration of the device are examined and discussed. Suggestions are given for preparing a planar pre-concentrator presenting the highest performances for the detection of benzene present as traces in a carrier gas.