Characteristics of Superficially-Porous Silica Particles for Fast HPLC: Some Performance Comparisons with Sub-2- m Particles

Abstract

Columns of 2.7-microm fused-core (superficially porous) Type B silica particles allow very fast separations of small molecules at pressures available in most high-performance liquid chromatography instruments. These highly-purified particles with 1.7-microm solid silica cores and 0.5-microm-thick shells of 9 nm pores exhibit efficiencies that rival those of totally porous sub-2-microm particles but at one-half to one-third of the column back pressure. This presentation describes other operating features of fused-core particle columns, including sample loading characteristics and packed bed stability. The superior mass transfer (kinetic) properties of the fused-core particles result in much-improved separation efficiency at higher mobile phase velocities, especially for > 600 molecular weight solutes.

Theory and Practice of UHPLC and UHPLC–MS

“…In comparison with totally porous particles of similar diameters, the diffusion path is much shorter because the inner core is solidfused silica, which is impenetrable by analytes (thus decreasing the C-term of the Van Deemter curve, mass transfer resistance) (Salisbury, 2008;Cavazzini et al, 2007). This obviously minimizes peak broadening, especially at elevated linear velocities (Destefano et al, 2008). This characteristic is particularly important for the separation of large molecules (i.e., peptides or intact proteins) because slow mass transfer induces a loss of efficiency with rapid separations on porous particles .…”

“…The real breakthrough of coreeshell particles for high efficiency separations of small molecules started in 2007 with the introduction of the HALO particles (2.7 mm with a shell thickness of 0.5 mm) by Advanced Materials Technology (Destefano et al, 2008;Kirkland et al, 2007). To date, many column vendors have introduced coreeshell particles in sizes ranging from 1.3 to 5 mm.…”

“…The differences in the h a -term for coreeshell particles have been frequently observed by other authors and are commonly attributed to a better column packing quality. There is an ongoing debate whether the improved column packing is related to a narrower particle size distribution (Destefano et al, 2008) or to higher surface roughness of the particles. Recently Desmet Ismail et al, 2016b) and Gritti and Guiochon (2015a,b) have reported on fully porous particles with a very narrow particle size distribution (Titan-C18) that also shows reduced plate heights well below 2.…”

Analysis of related substances in bisoprolol fumarate on sub-2-μm adsorbents

“…The reduction of the size of the adsorbent causes the decrease of mass transfer resis-tances and increases column efficiency. Further reduction in mass transfer resistances and increase in column efficiency are possible by introducing superficially porous particles [1][2][3][4][5][6][7][8]. The increase in column efficiency enables applying higher flow rates of the mobile phase, significantly reducing the analysis time.…”

Application of Fused-Core Particle Column in Two Dimensional Reversed Phase - Reversed Phase LC/MS Analysis of Biological Samples. Impact of Extra-Column Volume

“…2.6-2.7 micron fusedcore columns generate backpressures similar to those of a standard fully porous-3 µm column. The great advantage of fused core material is that these columns allow achievement of UHPLC-like resolution, without dramatic increase of the backpressure, therefore negating the necessity to purchase a UPLC/UHPLC system [1,2]. The relatively low pressure generated by fused core particles and the thin (about 0.5 µm) layer of stationary phase allows operation of fast flow rates without the loss of resolution by using standard HPLC equipment.…”