Size exclusion chromatography with superficially porous particles

Abstract

A comparison is made using size-exclusion chromatography (SEC) of synthetic polymers between fully porous particles (FPPs) and superficially porous particles (SPPs) with similar particle diameters, pore sizes and equal flow rates. Polystyrene molecular weight standards with a mobile phase of tetrahydrofuran are utilized for all measurements conducted with standard HPLC equipment. Although it is traditionally thought that larger pore volume is thermodynamically advantageous in SEC for better separations, SPPs have kinetic advantages and these will be shown to compensate for the loss in pore volume compared to FPPs. The comparison metrics include the elution range (smaller with SPPs), the plate count (larger for SPPs), the rate production of theoretical plates (larger for SPPs) and the specific resolution (larger with FPPs). Advantages to using SPPs for SEC are discussed such that similar separations can be conducted faster using SPPs. SEC using SPPs offers similar peak capacities to that using FPPs but with faster operation. This also suggests that SEC conducted in the second dimension of a two-dimensional liquid chromatograph may benefit with reduced run time and with equivalently reduced peak width making SPPs advantageous for sampling the first dimension by the second dimension separator. Additional advantages are discussed for biomolecules along with a discussion of optimization criteria for size-based separations.

Optimizing separations in online comprehensive two‐dimensional liquid chromatography

“…However, recent studies have shown the potential of fast SEC, using UHPLC technology . More recently, the use of core–shell particles in 2 D SEC to improve resolution was demonstrated and this was later confirmed . SEC is an intrinsically isocratic separation.…”

Superficially porous particles with 1000Å pores for large biomolecule high performance liquid chromatography and polymer size exclusion chromatography

“…As anticipated for SEC, the elution order is from largest solute to the smallest solute. A detailed experimental comparison of SEC between FPPs and SPPs has been conducted [24] and shows that SEC with SPPs offers advantages in speed, efficiency and plate production per unit time. The range of molecular weights used in Figure 12 spans the radius of gyration range [24] of 43 Å to 662 Å showing that the lowest MW standard of 17.5 kDa will fit into the smallest pore material in Figure 12.…”

“…A detailed experimental comparison of SEC between FPPs and SPPs has been conducted [24] and shows that SEC with SPPs offers advantages in speed, efficiency and plate production per unit time. The range of molecular weights used in Figure 12 spans the radius of gyration range [24] of 43 Å to 662 Å showing that the lowest MW standard of 17.5 kDa will fit into the smallest pore material in Figure 12. The largest MW standard is excluded by both pore systems with the caveat that the pore size distribution shown in Figure 3 demonstrates that a limited number of pores exist larger than 1000 Å.…”

Core–shell microspheres with porous nanostructured shells for liquid chromatography

“…The total pore volume is reduced for the core-shell particles, and hence a lower loading capacity, when compared to [174] the standard SEC porous particles. But this is usually compensated for by an increase in efficiency.…”