Characterizing the performance of industrial-scale columns

The performance of a large commercial chromatographic column was investigat ed using a short pulse of a tracer and an extension of the reverse-how tech nique. This technique permits separate determination of the unavoidable irr eversible microscopic processes and the reversible effects of Row maldistri bution, and allows for the separation of flow maldistribution in the Row di stributors from flow maldistribution inside the packed bed. This analysis w as performed on a 0.44 m Millipore IsoPak column using Cellufine CC 700, ce llulosic-based media with an average particle diameter of 75 mum, for the s tationary phase. The column efficiency was quantified by analysis of the ef fluent curve from a short pulse of a 5% aqueous acetone tracer. The study e xamined behavior of beds of different lengths (10-24 cm) and beds packed fr om different slurry concentrations (10-75% v/v). The slurry-packed columns were very uniform, and no significant macroscopic flow maldistribution was observed inside the column. The observed bed plate heights conformed to the predictions of available one-dimensional continuum models. Dispersion in t he Row distributors was significant, corresponding to 15-25% of the intraco lumn dispersion when the full 34 cm available bed length was used and a pro portionally larger increase for shorter bed lengths. Thus, the headers are shown to produce a significant increase in the observed plate height. (C) 2 001 Elsevier Science B.V. All rights reserved.