Superficially porous silica particles with wide pores for biomacromolecular separations

Abstract

Since 2006, columns of superficially porous particles (SPP), often called Fused-core®, porous-shell or core-shell particles, have had serious impact on HPLC separations. These particles have pore diameters of about 100 Å designed for separating small molecules. More recently, SPP with 160 - 200 Å pore diameter have been made available for separating peptides and small proteins. This report describes the effects of fused-core particle size, pore size, shell thickness and ligand type for the rapid, efficient separation of larger molecules such as intact proteins and other biomacromolecules up to at least 400 kDa. Optimization of these parameters resulted in particles that show no restricted diffusion that would compromise separating efficiency for large biomolecules. The thin porous shell provides excellent mass transfer (kinetics) for these large molecules, resulting in superior separations compared to conventional totally porous particles. Sample loading capacity can be adjusted to allow good detection sensitivity for minor components in a complex mixture. Strong particle strength ensures the loading of stable, high-efficiency columns. Stationary phases with different alkyl ligands were tested to provide data on retention, column efficiency and peak shapes for proteins. The development of these new wide-pore fused-core particles now allows the HPLC separation of a wide range of molecules of different sizes with advantages of the SPP configuration.

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

“…90 Ǻ) while packings with pore size 160 Ǻ were limited to solutes of MW <15000. 400 Ǻ materials were suitable for proteins with MW 400 kDa or higher 62 . Further work explored in more detail the added effect of shell thickness on performance using particles of diameter 3.4 m with different pore size over the range 90-400 Å and shell thickness 0.15 -0.5 m for the separation of proteins 63 .…”

Size exclusion chromatography with superficially porous particles

“…This is exemplified in reversed phase, normal phase and ion exchange chromatography where enthalpy-driven retention results in almost infinite retention until a critical concentration of the gradient is reached. As retention is reduced at or near the critical gradient composition, SPPs have been shown to offer substantial performance advantages in speed and efficiency for larger biomolecules (48–50). This is attributed to the mass transport advantages of having thin shells and shorter diffusion distances.…”

Core–shell microspheres with porous nanostructured shells for liquid chromatography

“…The effect of having wider pore size for the diffusion of large proteins up to at least 400 kDa such as ribonuclease A and insulin was investigated by Wagner et al. . In this study, Halo 2.7 μm C18 columns with pore size of 90, 160 and 400 Å were used and the results showed significant improvement in peak shape, resolution and selectivity (Fig.…”