Evaluation of the "effective volume shift" method for axial dispersion corrections in multi-detector size exclusion chromatography

Band broadening in size exclusion chromatography (SEC) causes errors in the calculated molar mass distribution even when molar-mass-sensitive detectors are used. These errors can be partially corrected by shifting the elution volume of the molar-mass-sensitive detector chromatogram relative to the concentration detector chromatogram, and then re-calculating the molar mass distribution. In this paper a computer simulation of multi-detector SEC of a polymer with a Flory-Schulz molar mass distribution and Gaussian band broadening is used to study the volume shift method of correcting for band broadening. The results are compared with those obtained by applying a conventional band broadening correction. In the case of SEC with a light scattering detector the results from the two methods are comparable. For SEC-viscometry with universal calibration the conventional method is significantly more accurate than the volume shift method. A method for calculating the volume shift required to correct for a known amount of band broadening is also presented. (C) 1999 Elsevier Science Ltd. All rights reserved.