Model for Nonequilibrium Binding and Affinity Chromatography: Characterization of 8-Hydroxyquinoline Immobilized on Controlled Pore Glass Using a Flow Injection System with a Packed Microcolumn

This paper discusses the use of pulse techniques for
analysis of zonal elution data for the determination of
mass-transfer and axial dispersion constants for porous
support materials with adsorption to the surface or to a
surface-bonded phase. As an example, this paper considers the case of controlled pore glass (CPG) with a bonded
phase that is used with microcolumns and a flow injection
analysis system. For the CPG, axial dispersion in the form
of eddy mixing can be described by l = 0.203, and the
overall mass-transfer term, KOL = 3.9 × 10-6 cm/s.
Additionally, an affinity chromatography model was adapted
to effectively describe systems employing CPG as the
support material through modification of equations describing typical affinity chromatography systems and by
inclusion of an axial dispersion term in the calculation of
N. This model was used to predict breakthrough curves
for cadmium adsorption by 8-hydroxyquinolinol immobilized on CPG packed in microcolumns. In general, the
information from the model can be used to extract
equilibrium-based constants (binding strengths and site
capacities) from a nonequilibrium flow system. The data
and model can also be employed in determining the
performance for scaled-up extraction systems. The modified model is available in EXCEL spreadsheet format as
Supporting Information.