Superficially porous silica particles with wide pores for biomacromolecular separations

Since 2006, columns of superficially porous particles (SPPs), 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, SPPs 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.