Thesis
The effect of flow rate on high performance liquid chromatography column re-equilibration after gradient elution
Master of Science (M.S.), Drexel University
Nov 2016
DOI:
https://doi.org/10.17918/etd-7280
Abstract
In traditional high-performance liquid chromatography (HPLC), column re-equilibration between gradient elution runs is necessary to prepare a column for subsequent experiments. This process replaces the final mobile phase in the column with the mobile phase employed at the start of the run. The replacement of mobile phase occurs in four regions within the column: (i) between the particles (inter-particle); (ii) within the pores of the particles (intra-particle); (iii) in the interfacial region between the mobile phase and stationary phase; and (iv) in the space between the bonded phase ligands. Column re-equilibration, which we hypothesize is limited by the rate of diffusion within the pores and in the interfacial region, traditionally consumes a large quantity of mobile phase due to the high flow rates commonly employed during the reequilibration process. An alternative approach to column re-equilibration after gradient elution is presented, in which solvent consumption is minimized by substantially reducing the flow rate during column re-equilibration, thus allowing more time for new mobile phase to diffuse into the pores and interfacial region while consuming less solvent. The effect of flow rate on reequilibration time and solvent consumption is studied using a variety of column sizes and stationary phase composition. In addition, the effect of the solvent identity (acetonitrile vs. methanol) and the magnitude of the change in mobile phase composition on the re-equilibration time are also evaluated. The volume of mobile phase needed for re-equilibration is shown to be proportional to the flow rate employed during the re-equilibration process, verifying that a reduction in solvent consumption can be achieved by lowering the flow rate. In addition, the time necessary for re-equilibration is shown to be influenced by two terms: one that is flow rate dependent, and the other that is flow rate independent.
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Details
- Title
- The effect of flow rate on high performance liquid chromatography column re-equilibration after gradient elution
- Creators
- Michael Robert Fletcher - DU
- Contributors
- Joe Preston Foley (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- ix, 27 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- College of Arts and Sciences; Chemistry; Drexel University
- Other Identifier
- 7280; 991014632552704721