Certification of contents of aromatic hydrocarbons in charcoal tubes - CRM562

A Certified Reference Material (CRM) for determination of aromatic hydrocar bons in air was developed. The CRM 562 consists of aromatic hydrocarbons so rbed on charcoal in glass tubes. Initial feasibility studies established th at a homogeneous and stable batch could be prepared. Three intercomparisons prior to the certification allowed the identification of various sources o f error. Then, a batch of about 3000 tubes was charged and certified on the basis of analyses carried out in 15 European laboratories. The preparation of the reference material and the results of the certification exercise is described. An overview on the analytical techniques used and the quality c ontrol guidelines are also presented. The certified values are 15.0 +/- 0.4 mu g benzene, 147.3 +/- 3.8 mu g toluene, 96.4 +/- 2.5 mu g m-xylene and 9 3.0 +/- 2.9 mu g o-xylene per tube. This reference material is recommended for quality control of measurements in the field of occupational hygiene.