Performance characteristics of new superficially porous particles

Abstract

Superficially porous particles (also called Fused-Core, core shell or porous shell particles) show distinct advantages over comparable totally porous particles for separating small molecules. Columns of Fused-Core particles exhibit very high efficiency because of superior eddy dispersion properties (smaller van Deemter A term). The efficiency for columns of 2.7 μm Fused-Core particles actually rivals that for sub-2 μm totally porous particles with only about one-half the back pressure. These Fused-Core particles show special advantages with larger molecules for fast separations at high mobile phase velocities because of superior mass transfer (kinetic) properties (smaller van Deemter C term). This report describes the effect of different particle size and porous shell thicknesses on chromatographic performance for Fused-Core particles. Particle characteristics can significantly affect factors of separation importance. For example, the reduced plate height of packed columns is affected by particle diameter. Interestingly, larger Fused-Core particles show smaller reduced plate heights than smaller Fused-Core particles. Also, porous shell thickness has a strong effect on solute retention as well as separation efficiency, and particle surface area has a direct influence on sample loading characteristics. Fused-Core particles with a wide range of physical characteristics have been developed that allows the preparation of stable, efficient packed columns.

Core–Shell, Ultrasmall Particles, Monoliths, and Other Support Materials in High-Performance Liquid Chromatography

“…In general, studies have suggested a compromise between a short diffusion path (which leads to high efficiency) and adequate retention / mass load tolerance. Shell particles with thinner porous shells show marginal improvement in column efficiency for small molecules, but improved performance for larger molecules which have much smaller diffusion coefficients and thus give higher mass transfer contributions to band broadening 59 . This particular study indicated the best compromise for large molecules was a 0.2 m shell thickness.…”

Sub-2-μm seeded growth mesoporous thin shell particles for high-performance liquid chromatography: Synthesis, functionalisation and characterisation

“…Wu and Clausen [12] demonstrated that use of all silica particles with smaller diameter to achieve efficient separation always leads to increased back pressure. DeStefano et al [13] have shown that as particle size of superficially porous silica decreases, column efficiency increases but the operating pressure increases drastically as a square of the particle size. Unger et al demonstrated that halving the particle size may double separation performance (in terms of column efficiency or theoretical plate numbers), and http://dx.doi.org/10.1016/j.chroma.2015.04.034 0021-9673/© 2015 Elsevier B.V. All rights reserved.…”

Possibilities of retention prediction in fast gradient liquid chromatography. Part 3: Short silica monolithic columns

“…Recently, we investigated the accuracy of prediction of gradient data in fast gradient chromatography (1−2 min) on short columns packed with fully porous [2] or superficially porous (core−shell) particles [3,4] with different chemistries of bonded stationary phases. We found that either 5 or 3 cm core-shell columns may provide comparable peak capacity in a fixed short gradient time with optimized gradient range.…”