Retention modeling under organic modifier gradient conditions in ion-pair reversed-phase chromatography. Application to the separation of a set of underivatized amino acids |
| |
Authors: | A Pappa-Louisi P Agrafiotou K Papachristos |
| |
Institution: | (1) Laboratory of Physical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece |
| |
Abstract: | The combined effect of the ion-pairing reagent concentration, C
ipr, and organic modifier content, φ, on the retention under φ-gradient conditions at different constant C
ipr was treated in this study by using two approaches. In the first approach, the prediction of the retention time of a sample
solute is based on a direct fitting procedure of a proper retention model to 3-D φ-gradient retention data obtained under the same φ-linear variation but with different slope and time duration of the initial isocratic part and in the presence of various
constant C
ipr values in the eluent. The second approach is based on a retention model describing the combined effect of C
ipr and φ on the retention of solutes in isocratic mode and consequently analyzes isocratic data obtained in mobile phases containing
different C
ipr values. The effectiveness of the above approaches was tested in the retention prediction of a mixture of 16 underivatized
amino acids using mobile phases containing acetonitrile as organic modifier and sodium dodecyl sulfate as ion-pairing reagent.
From these approaches, only the first one gives satisfactory predictions and can be successfully used in optimization of ion-pair
chromatographic separations under gradient conditions. The failure of the second approach to predict the retention of solutes
in the gradient elution mode in the presence of different C
ipr values was attributed to slow changes in the distribution equilibrium of ion-pairing reagents caused by φ-variation. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|