Experiment 18 - Gel permeation chromatography

Abstract

The molecular weight (MW) and molecular weight distribution (MWD) are regarded as the fundamental characteristics of a polymer sample. Gel permeation chromatography (GPC), more correctly termed “size exclusion chromatography” (SEC), is essentially a separation method for polymers and provides a relative molecular weight. The term gel permeation chromatography was defined by Moore, who developed rigid cross-linked polystyrene gels with a range of pore sizes, suitable for separation of synthetic polymers in organic media. It is noted that GPC is extremely valuable for both analytic and preparative work with a wide variety of systems ranging from low to very high molecular weights. The method can be applied to a wide variety of solvents and polymers, depending on the type of gel used. GPC is also used for routine polymer characterization and quality control, particularly in determinations of MWD and for characterizing low polymers and small molecules. The use of multidetector GPC greatly increases the power of SEC, particularly in the case of copolymers.