Corrections for Instrumental and Secondary Broadening in the Chromatographic Analysis of Linear Copolymers

Abstract

The effects of instrumental broadening and of polymer/solvent/packing interactions (secondary broadening) are separately investigated in the context of chromatography experiments, for the characterization of linear copolymers with two types of repeating units. The problems associated to the estimation of: a) the joint molecular weight distribution - chemical composition distribution (MWD-CCD) through orthogonal chromatography; and of b) the average MWD - average CCD through standard size exclusion chromatography (SEC) with dual detection are considered. The main difficulty with the secondary broadening correction, is the calibration for this effect. In the case of standard SEC with dual detection, a simple solution was found to the instrumental broadening problem, that involves a direct extension of the calibration and deconvolution techniques developed for linear homopolymers and mass detectors.