## Abstract Supercritical xenon and CO~2~ are compared as solvents by means of solubilities (calculated by means of the PengβRobinson equation of state) and chromatographic behavior for some polynuclear aromatic hydrocarbons; reasons for the apparent superiority of xenon are discussed. The advantag
Functional group selectivity using fluoroform as a mobile phase for supercritical fluid chromatography
β Scribed by John A. Blackwell; Luke E. Schallinger
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 513 KB
- Volume
- 6
- Category
- Article
- ISSN
- 1040-7685
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
The eluotropic strenght and chromatographic selectivity of fluoroform is compared to that of carbon dioxide and methanolβmodified carbon dioxide. Naphthalene derivatives were used as probe solutes in capillary supercritical fluid chromatography to determine the effects of fluid type, pressure, and temperature on selectivity and retention. Fluoroform is much stronger in eluotropic strengh than carbon dioxide or methanolβmodified carbon dioxide at the same temperature and pressure. Under the same reduced conditions, fluoroform is lower in eluotropic strength than carbon dioxide. Specific interactions between hydrogen bond accepting functional groups and fluoroform are observed. Functional groups capable of accepting hydrogen bonds contribute less of an increase in retention when using fluoroform while those capable of dispersive interactions contribute less of an increase in retention when using carbon dioxide.
π SIMILAR VOLUMES
A small percentage (0.3 % w/w) of formic acid was added to supercritical carbon dioxide to increase mobile phase polarity and improve separation of polar solutes on three different commercially available capillary columns. Formic acid reduced retention and altered selectivity for several polar compo
A variety of acidic mobile phase additives were investigated as to their effects on retention, selectivity, efficiency, and overall chiral resolution for a number of chiral N-substituted phenylalanine analogs under subcritical conditions. These mobile phase additives showed significant effects for a