ISSN:
0935-6304
Schlagwort(e):
Capillary gas chromatography
;
Cold trapping
;
Sampling in stainless steel canisters
;
Calibration
;
Halocarbons in remote areas
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
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 CO2 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.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jhrc.1240130108
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