Desorption characteristics of four polyimide sorbent materials using supercritical carbon dioxide and thermal methods.
Raymer-JH; Pellizzari-ED; Cooper-SD
Anal Chem 1987 Oct; 59(17):2069-2073
A study was made to determine whether supercritical carbon-dioxide (CO2) desorption was equally applicable to the more highly retentive polyimides as it is applicable to Tenax-GC for the desorption of 1,2,3,4,5,6-hexachlorocyclohexane (608731), hexachlorobiphenyl, anthracene (120127), and parathion (56382). Carbon-14 labeled compounds were used for the recovery determinations. The identification of the compounds desorbed with supercritical CO2 was verified by using thin layer chromatography and mass spectrometry. The results were compared to those from Tenax-GC studies. The results indicated that supercritical fluid desorption method was superior to thermal desorption. Both types of desorption were more difficult from the polyimides than from Tenax-GC used in previous works. Anthracene was very poorly desorbed from the polymers, which indicated a high energy of adsorption. Results indicated that supercritical CO2 can be used to desorb three of the four test analytes from the polyimides, with recoveries being better using polymers of lower overall retention. Recoveries with thermal desorption were very poor for all of the sorbents with low desorption volumes; with larger desorption volumes, there was some improvement.
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