Related Experiment Video
Updated: Jun 17, 2026

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels
Published on: September 8, 2016
Determination of the interparticle void volume in packed beds via intraparticle Donnan exclusion
Stephanie Jung1, Steffen Ehlert, Martin Pattky
1Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany.
Abstract:
Interparticle void volumes and porosities of packed capillaries have been determined using intraparticle Donnan exclusion of a small, unretained, co-ionic tracer (nitrate ions). The operational domain of this approach has been characterized for bare silica, reversed-phase, and strong cation-exchange materials (with different particle sizes and intraparticle pore sizes) in dependence of the mobile phase ionic strength. Interparticle porosities agree well with those analyzed by inverse size-exclusion chromatography (ISEC). Limitations to the use of Donnan exclusion (electrostatic exclusion) and ISEC (mechanical exclusion) arise as either type of exclusion becomes noticeable also in the cusp regions between the particles, or as the intraparticle pores are so large that complete electrostatic and size-exclusion are difficult to realize. Our data confirm that intraparticle Donnan exclusion presents a most simple, fast, and reliable approach for the analysis of packing densities.
More Related Videos
Related Concept Videos
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
In Vitro Drug Dissolution: Compendial Testing Models II
Total Voids in Concrete
In Vitro Drug Dissolution: Alternative Methods
Real Gases: Effects of Intermolecular Forces and Molecular Volume Deriving Van der Waals Equation
Determination of Molar Masses of Polymers II

