The obstruction factor in size-exclusion chromatography. 1. The intraparticle obstruction factor

Does the “C3 effect” offset the Δ2 effect, as regards the solution flexibility of aldoses?

“…Using three different methods, namely the published relationship between radius of gyration ( R G ) and molar mass ( M ) for PEO in water, obtained from static light scattering measurements; the published Mark–Houwink relationship between the intrinsic viscosity and M of PEO in water (obtained from both viscometry and static light scattering measurements), from which R G is calculated using Flory–Fox/Ptitsyn–Éizner theory , ; and a random walk calculation with fixed bond angles and hindered bond rotation; we obtain an R G of ≈28 Å for the smallest PEO/PEG excluded from the pores, suggesting a pore size of at least 60 Å. In actuality, recent experiments by our group have suggested an “ink bottle” structure for the pores of SEC column packing materials made from crosslinked gels, with the interior pore diameter being larger that the diameter of the opening cavity of the pore . When compared with the 3–5 Å hydrodynamic radii of the analytes, the order‐of‐magnitude difference in size between the sugars and the pores means that confinement effects, if at all present, should be minimal.…”

Electrophoretic Migration and Axial Diffusion of Individual Nanoparticles in Cylindrical Nanopores

“…It has been shown that the intraparticle obstruction factor in size-exclusion chromatography can result in up to a factor of 100 difference in apparent diffusion coefficients inside the pores versus in bulk . Here, tortuosity and constriction can be ruled out, vide supra .…”

“…It has been shown that the intraparticle obstruction factor in size-exclusion chromatography can result in up to a factor of 100 difference in apparent diffusion coefficients inside the pores versus in bulk. 55 Here, tortuosity and constriction can be ruled out, vide supra. If the Smoluchowski equation (eq 5 corrected by eq 9) and Einstein−Stokes equation (eq 11) both hold in the nanopore environment: μ πη = q R 6 Pore (13) where the subscript "Pore" denotes the apparent values measured in the nanopores, we can obtain the apparent viscosity η Pore from both the electrophoretic migration and the diffusion experiments.…”