Abstract
The partition and adsorption mechanisms of retention in reversed-phase liquid chromatography have been examined based on a comparison of the free energy of transfer of methylene groups from aqueous-organic mixtures to bulk hexadecane with those to a variety of polymeric bonded phases. The stationary phases studied include: conventional silica-based polymeric phases of various alkyl chain lengths, a so-called 'horizontally polymerized' octadecyl phase on silica and a series of polybutadiene-coated zirconia phases. The data indicate that for methylene groups a partition-like mechanism is dominant on all phases. On the polybutadiene-coated zirconia and 'horizontally polymerized' octadecyl phases the partition mechanism holds at all mobile phase compositions. In contrast on conventional polymeric silica phases the retention mechanism seems to become more adsorption-like at methanol compositions greater than about 70% (v/v).
Original language | English (US) |
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Pages (from-to) | 1-10 |
Number of pages | 10 |
Journal | Journal of Chromatography A |
Volume | 767 |
Issue number | 1-2 |
DOIs | |
State | Published - Apr 11 1997 |
Bibliographical note
Funding Information:P.W.C. acknowledgessu pportb y a grantf rom the National Science Foundation.J. H.P. acknowledges support by a grant (01-D-0657)f rom the Korea ResearchF oundation.
Keywords
- Free energy of transfer
- Retention mechanisms
- Solvophobic driving forces
- Stationary phases, LC
- Thermodynamic parameters