ABSTRACT
Size exclusion chromatography (SEC) provides a rapid, high-resolution method for determining molecular weight distributions (MWD) of macromolecules. In the conventional mode, the molecular weight is determined by calibrating the column to determine the relation between elution volume and molecular weight. The size exclusion separation mechanism is based on the effective hydrodynamic volume of the molecule, not the molecular weight, and as a result the system must be calibrated using standards of known molecular weight and homogeneous chemical composition. The chemical composition must be the same as the standards to he analyzed, and the calibrated molecular weight range must be greater than the range of molecular weights to be analyzed. The calibration curve is thus specific to a given polymer-solvent system.
