title: Experimental investigation of the difference in B-term dominated band broadening between fully porous and porous-shell particles for liquid chromatography using the Effective Medium Theory.
abstract: The difference in B-term diffusion between fully porous and porous-shell particles is investigated using the physically sound diffusion equations originating from the Effective Medium Theory (EMT). Experimental data of the B-term diffusion obtained via peak parking measurements on six different commercial particle types have been analyzed (3 porous and 3 non porous). All particles were investigated using the same experimental design and test analytes, over a very broad range of retention factor values. First, the B-term reducing effect of the solid core (inducing an additional obstruction compared to fully porous particles) has been quantified using the Hashin-Shtrikman expression, showing that the presence of a solid core can account for a reduction of about 11% when the core diameter makes up 63% of the total particle diameter (Halo and Poroshell-particles) and a reduction of 16% when the core diameter makes up 73% (Kinetex). Remaining differences can be attributed to differences in the microscopic structure of the meso-porous material (meso-pore diameter, internal porosity or relative void volume). The much lower B-term diffusion of Halo and Kinetex particles compared to the fully porous Acquity particles (some 20-40% difference, of which about 10-15% can be attributed to the presence of the solid core) can hence largely be attributed to the much smaller internal porosity and the smaller pore size of the meso-porous material making up the shell of these particles.
authors.affiliation: Vrije Universiteit Brussel, Department of Chemical Engineering, Brussels, Belgium.
authors.forename: Anuschka
authors.initials: A
authors.lastname: Liekens
authors.forename: Joeri
authors.initials: J
authors.lastname: Denayer
authors.forename: Gert
authors.initials: G
authors.lastname: Desmet
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation*; D004058:Diffusion; D008863:Microspheres; D008956:Models, Chemical; D010226:Parabens; D010316:Particle Size; D016062:Porosity
chemical_list: D010226:Parabens; C015358:methylparaben