Analysis of C1- and C2-halocarbons in ambient air from remote areas using stainless steel canister sampling, cold trap injection HRGC, and a static calibration technique
✍ Scribed by Müller, S. ;Oehme, M.
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 583 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0935-6304
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✦ Synopsis
Abstract
5 ml air samples from 1.6 l stainless steel canisters were cryogenically preconcentrated before gas chromatographic separation on a thick‐film capillary using a home‐made cryotrap. Quantification in the 10–500 ppt range was carried out with an electron capture detector. Problems during the cryotrap step were caused by carrier gas contamination, water and CO~2~ content of the sample, and a non‐optimal heat desorption rate. Their elimination is described in detail. Compound losses by wall adsorption on stainless steel surfaces were observed when dry gases were used for standard generation. A static multipoint calibration technique using humidified He was developed allowing a precise standard generation down to 100 ppt. The concentration changes in the stainless steel canisters could be neglected over a storage period of at least 1 month as long as a sufficient degree of humidity was present. The overall reproducibility of the quantification and calibration technique is in the order of 1–2% for concentrations between 100–400 ppt when daily recalibrations are carried out.