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Characterization of polymer monolithic columns for small-molecule separations using total-pore-blocking conditions

Journal Contribution - Journal Article

This study involves the investigation of the meso- and micropores in polymer monolithic materials and the performance characterization of polymer monoliths for the separation of small molecules. Pore-blocking experiments, that involve the blocking of the stagnant pores with a solvent which is immiscible with the mobile phase, were conducted to determine interstitial volumes of a commercially-available polymer monolithic column. After blocking the meso- and micropores a clear reduction in the column void time was observed. Using this approach, the internal porosity (defined as the sum of the meso- and micropores with respect to the volume of the monolithic material) was determined at 12.5%. Peak-dispersion measurements were conducted by applying reversed-phase (RP) conditions. The high plate-height values for small-molecule separations are mainly attributed to the large eddy-diffusion and mobile-phase mass-transfer contributions to band broadening, related to the inhomogeneous structure and presence of parabolic profiles in the macropores. The C-term contribution of early eluting (retained) compounds was higher than that of the late eluting compounds. This could be attributed to the low zone-retention factors of early-eluting compounds and consequently a large stationary-phase mass-transfer contribution. However, peak-dispersion measurements with blocked meso- and micropores carried out at RP conditions indicated that the Cs-contribution alone is likely not be the main cause of peak broadening. Finally, 1H spin-spin (T2) relaxometry NMR measurements were conducted with water and ACN in the monolithic material.
Journal: Journal of chromatography
ISSN: 0021-9673
Volume: 1325
Pages: 115-120
Publication year:2014
Keywords:Gel porosity, Absorption, Polymer monolith, Column
  • ORCID: /0000-0002-5465-0127/work/74203718
  • ORCID: /0000-0001-8781-7184/work/69211580
  • ORCID: /0000-0003-0524-7830/work/69122000
  • Scopus Id: 84891827502