Longitudinal diffusion in size-exclusion chromatography: a stop-flow size-exclusion chromatography study

Band broadening in size-exclusion chromatography (SEC) has an adverse effec t upon calculated molecular mass averages, distributions, and dilute soluti on data generated using single- and multi-detector systems. In the past, th e longitudinal diffusion contribution to band broadening in SEC has been co nsidered negligible. This assumption has been investigated by using a stop- flow methodology (SF-SEC) that maximizes the potential for longitudinal dif fusion while minimizing that for mass transfer. Under the given experimenta l conditions, the effects of B-term band broadening were manifest only belo w 30 KDa, irrespective of chemical functionality or molecular mass polydisp ersity. This type of broadening was found to be flow rate-independent for a representative high molecular mass polymer. (C) 2001 Elsevier Science B.V. All rights reserved.