The inverse application of the size-exclusion chromatography (SEC) concept, inverse size-exclusion chromatography (ISEC) [1], utilizes a set of molecular probes with defined sizes to determine pore dimensions, and is also referred as chromatographic porosimetry [2]. ISEC provides an alternative to mercury porosimetry or nitrogen adsorption for the determination of the pore size dimensions and the surface area of [...]
Superficially porous particles with thicker outer shells were used extensively for liquid-liquid chromatography [1] and as the support for early bonded-phase packings in reverse phase HPLC [2]. Structure of particles Nowadays superficially porous particles typically have a 5-µm solid core and a ~ 0.25 – 1 µm thick outer shell with 30-nm pores. But, the thinner the shell, the [...]
It is known that the kinetics of mass transfer in wide pore bonded silica can be slow, because of restricted intraparticle diffusion and, furthermore, remaining active surface sites can give rise to undesired interactions. All together, these effects cause additional peak dispersion in high performance liquid chromatography and often considerable loss in recovery of biological [...]
Many applications of porous materials in areas such as catalysis, adsorption, ion exchange, chromatography, and solid phase synthesis rely on the intimate contact with a surface that supports the active sites. In order to obtain large surface area, a significant number of smaller pores should be incorporated into the polymer. Types of pores The most substantial contribution to the [...]
The generally accepted mechanism of pore formation in organic polymer monolihts during a typical polymerization in the presence of a precipitant is following [1,2]: The organic phase contains both monovinyl and divinyl monomers, initiator and porogenic solvent. The free-radical initiator decomposes at a particular temperature and the initiating radicals start the polymerization process in solution. Nuclei formation The polymers [...]
As a new type of chromatographic stationary phase, monoliths have been subjected to intensive study in the last years. They differ from other supports mainly in their characteristic structure, which results in the improved chromatographic properties. While most of the chromatographic supports are particle shaped, monoliths consist of a single piece of highly porous material. In contrast to porous [...]
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Chromatographic articles