MONOTERPENES IN AIR SAMPLES - EUROPEAN INTERCOMPARISON EXPERIMENTS

An intercomparison experiment on preconcentration of monoterpenes from air samples was carried out by three European laboratories (Technisch e Universitat Munchen [TUM], Institut National Polytechnique de Toulou se [INP], Joint Research Center Ispra [JRC]) using Tenax porous polyme r as an adsorbent. Sampling procedures, gas chromatographic analysis a nd standardisation methods differed in each laboratory and were compar ed in this study. Tenax adsorption tubes loaded with up to 10 monoterp enes (tricyclene, alpha-pinene, beta-pinene, camphene, sabinene, myrce ne, DELTA3-carene, p-cymene, 1,8-cineole and limonene) were created in dependently and exchanged for analysis between the working groups. For most monoterpenes the recoveries found by the different laboratories were 100%. The precision of analyses was better than 20%. Independent determinations of alpha-pinene mixing ratios in the air of the crown r egion in a natural spruce stand corresponded satisfactorily. Monoterpe ne emission rates of attached twigs in the sun crown of field grown sp ruce trees were also determined with good agreement.