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Publikace detail

New types of organic polymer monolithic columns for capillary HPLC
Autoři: Jandera Pavel | Staňková Magda | Currivan Sinéad Ann | Urban Jiří
Rok: 2015
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng New types of organic polymer monolithic columns for capillary HPLC Monolithic columns for HPLC do not contain particles, but consist of a single piece of continuous separation media (rods). The structure of monolithic media can be represented as a network of small mesopores, which are responsible for the retention and separation selectivity, interconnected by large flow-through pores. This dual pore morphology provides good bed permeability and lower flow resistance than the conventional LC columns packed with small particles, providing thus significantly faster separations at high flow of the mobile phase and moderate back-pressures, in comparison to particle-packed columns with similar efficiency [P. Aggarawal, H.D. Tolley, M.L. Lee, J. Chromatogr. 1219 (2012) 1.]. Two types of monolithic materials are available for chromatographic separations - monoliths based on inorganic precursors and those based on organic polymers, which show significant differences in pore morphology. Silica gel monoliths have a bimodal pore structure with significant representation of 7 – 12 nm mesopores (~13%) and relatively high specific surface area of several hundred m2/g, similar to the specific surface area 150 – 400 m2/g, typical for particles packed in conventional columns [H. Minakuchi, K. Nakanishi, N. Soga, N. Ishizuka, N. Tanaka, Anal. Chem. 68 (1996) 3498. G. Guiochon, J. Chromatogr A, 1168 (2007) 101.]. The reduced mesopore depth in the monolithic structures also reduces the resistance to mass transfer term, so that elevated flow rates can be used without the loss of performance. Hence the silica monoliths are ideal for separations of small molecules, as the mesopore size allows easy penetration to the adsorption sites and fast diffusion, resulting in fast separations of lowmolecular samples with column efficiencies up to 100,000 theoretical plates/m [H. Minakuchi, K. Nakanishi, N. Soga, N. Ishizuka, N. Tanaka, J. Chromatogr. A, 762 (1997) 135.].