Abstract |
Solid adsorbent beds are a practical, commonly used way to concentrate organic molecules from large volumes of air to make analysis possible. A small set of such beds exposed simultaneously, but each at a quite different flow rate, has been suggested as a way to assess the presence of complications. This sampling approach represents a strong quality assurance activity because it provides a summary index of the effects of a sizable number of variables to aid in quality assessment. Implementation is quite practical. Costs are not trivial since sets of four samples are preferred. However, some complications easily discovered but not specifically identifiable by this approach might elude more conventional quality control checking. Examples would be selective contamination, inadequate retention and artifact reactions. Results from tandem tube and non-tandem tube sets are presented to illustrate these suggestions. |