Porous Silica Particles As Chromatographic Separation Media: A Review

Abstract

Porous silica particles are the most prevailing raw material for stationary phases of liquid chromatography. During a long period of time, various methodologies for production of porous silica particles have been proposed, such as crashing and sieving of xerogel, traditional dry or wet process preparation of conventional spherical particles, preparation of hierarchical mesoporous particles by template-mediated pore formation, repeated formation of a thin layer of porous silica upon nonporous silica core (core-shell particles), and formation of specific silica monolith followed by grinding and calcination. Recent developments and applications of useful porous silica particles will be covered in this review. Discussion on sub-3 µm silica particles including nonporous silica particles, carbon or metal oxide clad silica particles, and molecularly imprinted silica particles, will also be included. Next, the individual preparation methods and their feasibilities will be collectively and critically compared and evaluated, being followed by conclusive remarks and future perspectives.

An optimized mixed‐mode stationary phase based on silica monolith particles for the separation of peptides and proteins in high‐performance liquid chromatography

“…The last strategy was to use ground silica monolith particles as the substrate for ligand modification. We have been studying ground silica monolith particles as new stationary phase media [19][20][21][22][23][24][25][26][27]. Ground silica monolith particles, a special type of packing material, have higher permeability (2.4 × 10 −14 m 2 for 3.9 µm C18 modified silica monolith particles) and separation efficiency (up to 195 000 plates/m) than spherical porous silica particles [27].…”

Styrene‐N‐phenylacrylamide co‐polymer modified silica monolith particles with an optimized mixing ratio of monomers as a new stationary phase for the separation of peptides in high performance liquid chromatography

“…The stationary phases based on ground silica monolith particles may be adopted to solve the column packing difficulties. Such stationary phases have been developed in our laboratory [15][16][17][18][19][20][21][22][23]. Their unique character of multiple particle shapes causes a partially monolithic structure in the packed bed enabling fast slurry flux during packing to result in improved packing quality.…”

Sub-2 μm Silica Particles in Chiral Separation

“…On the other hand, in porous particles, solutes transfer from the mobile phase exterior to the particles into the mobile phase within the pores to interact with the chiral stationary phase (CSP) [9]. Following this interaction, the solute molecule must diffuse out of the particle and continue its journey down the column ahead of the solute [5,9]. This slow rate of mass transfer into and out of the porous particle is a source of HPLC band broadening [9].…”

“…Following this interaction, the solute molecule must diffuse out of the particle and continue its journey down the column ahead of the solute [5,9]. This slow rate of mass transfer into and out of the porous particle is a source of HPLC band broadening [9]. Figure 2 illustrates a reduction in particle size shortens the path length of this diffusion process, improves mass transfer, and provides better efficiency [9].…”

“…This slow rate of mass transfer into and out of the porous particle is a source of HPLC band broadening [9]. Figure 2 illustrates a reduction in particle size shortens the path length of this diffusion process, improves mass transfer, and provides better efficiency [9].…”