ABSTRACT
Gel permeation chromatography (GPC), alternatively called size exclusion chromatography, is a separation method in which the porous structure of the stationary phase interacts with molecules of the solute; the extent of their retention or the rate of migration is determined by their effective sizes in solution. Research on universal calibration has contributed, in a decisive manner, to the elucidation of some aspects of the mechanism of separation in GPC; it has also helped to reveal further possibilities offered by GPC for the determination not only of molecular weight distribution of polymers, but also of their structure. In addition to the determination of branching of homopolymers, GPC fractionation may be used under certain conditions in the determination of chemical composition and of the distribution of chemical composition of copolymers. The on-line coupling of GPC and some type of automatic flow-through viscometer obviously may be used in the determination of polymer branching, if the principle of universal calibration is employed.
