Premium
Fast, accurate, and convenient analysis of bed densities for columns packed with fine reversed‐phase particles
Author(s) -
Jung Stephanie,
Stoeckel Daniela,
Tallarek Ulrich
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201000853
Subject(s) - packed bed , chromatography , chemistry , phase (matter) , materials science , analytical chemistry (journal) , organic chemistry
We determine the interparticle porosities of commercially available, analytical, reversed‐phase HPLC columns by Donnan exclusion of a small, unretained, co‐ionic tracer (nitrate ions). The columns contained packings of C 18 ‐modified, endcapped, silica particles, which differed in their nominal particle diameters (1.8–5 μm) and construction (fully porous or core‐shell). Experiments were carried out by monitoring the elution volumes of nitrate samples in a mobile phase of acetonitrile/water 80:20 v/v at increasing concentrations of Tris‐HCl buffer (pH 8.1) from 0.01 to 60 mM. At low buffer concentrations, nitrate ions are completely electrostatically excluded from the intraparticle mesopore space, which is reflected by a plateau region in the elution curves. The elution volume in the plateau region equals the interparticle void volume. Clearly defined plateau regions were observed for all columns, even those densely packed with core‐shell and sub‐2 μm particles, enabling the accurate determination of interparticle porosities to three decimal places in a fast and convenient way.