SAMPLING AND ANALYSIS OF ISOPRENE IN AMBIENT AIR

Tenax TA, Tenax GR (graphitised Tenax), Carbotrap B and Carbosieve S w ere tested as adsorbing materials for the analysis of 2-methyl-1.3-but adiene (isoprene) in air samples. Carbotrap B was found to be the most suitable adsorbing material showing high adsorption efficiency (break through volume > 1 litre) while breakthrough volumes for Tenax TA and Tenax GR were 20 ml and 250 ml, respectively. Carbosieve S produces hi gh background and is extremely sensitive to water vapour. Even at very low concentrations of isoprene (0.1-0.5 ng/tube), ozone at levels up to 240 ppbv did not cause any negative effects i.e. degradation of the adsorbed isoprene.