Community Research and Development Information Service - CORDIS


Back diffusion during analysis of Perkin-Elmer (PE) tubes has been observed when using the ATD-400 desorber system. The experimental decay observed in the test is dependent on several factors such as:

- Airtightness of the PE caps (it can change between different tubes during the experiment and it will also depend on the number of times that the caps have been used);
- How temperature affects the adsorption isotherm (the increase in temperature of the tube on approaching the desorption oven results in a higher back diffusion effect);
- Whether the caps have been cleaned (occasionally, remains of adsorbents released by the tubes can remain in the caps and increase the back diffusion);
- Background level of pollutants in the laboratory (high concentration levels of contaminants in the laboratory can produce the opposite effect causing the samples to be contaminated while waiting in the carousel for analysis).

All these problems can seriously affect the true nature of the results. Nevertheless, they can be easily resolved by guaranteeing the airtightness of the PE caps. caps.

Additional information

Authors: BALLESTRA P P, JRC Ispra (IT)
Bibliographic Reference: Article: Diffusive Monitor
Record Number: 199711364 / Last updated on: 1997-10-23
Original language: en
Available languages: en