Simulation of Size Exclusion Chromatograms from Viscometry and Refractometry Detectors: An Analysis of the Influence of Concentration Errors on Reliability of Estimated Parameters

Abstract

Size exclusion chromatograms of polymer samples of known molecular weight distribution (MWD), in solutions of known Mark-Houwink constants, as obtained from viscometry and refractometry detectors, have been simulated to check the influence of some errors in the solution concentration on the evaluation of the sample molecular characteristics and of the solution properties. It has been found that concentration errors arising from uncorrect estimate of the weight of injected polymer yield proportional errors on the average molecular weights and the Mark-Houwink K constant, but do not affect the MWD and the a exponent Concentration errors arising from uncorrect estimate of the difference between the times occurring to identical macromolecules to reach the detectors strongly modify the MWD, with consequences on the evaluation of both molecular characteristics and Mark-Houwink constants, and give rise to curvatures in the Mark-Houwink plots, thus suggesting a check, during the treatment of the chromatograms, of the reliability of the time difference estimate.