What is the best sorbent for pumped sampling–thermal desorption of volatile organic compounds? Experience with the EC sorbents project

Abstract

A project supported under the EC Measurements and Testing Programme and involving 12 participants has evaluated potentially useful sorbents for the collection and measurement of airborne volatile organic compounds (VOCs) in the workplace. The standard method uses Tenax as sorbing agent, but this is not suitable for very volatile or very polar compounds because of its low capacity for these compounds. Consensus on the best sorbents has been reached on the basis of an evaluation of sorbent performance, using about 20 test compounds with a wide range of volatilities and polarities. The sorbent which satisfied the agreed acceptance criteria for the largest number of compounds was Chromosorb 106. It is therefore recommended for use when sampling the more volatile and polar organic vapours encountered in workplace atmospheres. However, a number of other sorbents also satisfied the acceptance criteria for the majority of compounds and are suitable for a more limited (Higher molecular mass) range of organic vapours. These sorbents included Carbotrap, Tenax GR, Tenax TA and Carbopack B. Carboxen 569 was found suitable for sampling the most volatile compounds (ethylene oxide, methanol and propane).