gelpermeasjonskromatografi

Gel permeation chromatography (GPC), also known as size-exclusion chromatography (SEC) in polymer science, is a chromatographic technique used to separate dissolved polymers and other macromolecules by their hydrodynamic volume. In GPC, a solution passes through a column packed with porous beads. Large molecules are excluded from many pores and elute earlier, while smaller molecules penetrate more pores and elute later. The elution profile provides information related to molecular size, which can be related to molecular weight with calibration.

Columns are filled with crosslinked polymer or silica beads with defined pore size distributions. The mobile phase is a suitable solvent that dissolves the sample and is compatible with the column. Detectors such as refractive index, UV, light scattering, and viscometry are used to measure concentration and, in some configurations, measures of intrinsic viscosity or molecular weight. Data are expressed as molecular weight distributions, from which statistics such as number-average molecular weight Mn, weight-average Mw, and polydispersity Đ = Mw/Mn are derived.

GPC is widely used in polymer science and related fields to characterize polymer molecular weight distributions, to assess polymerization control, and to study degradation. It can also be used for nanoparticles, proteins, and other macromolecules, though solubility and interactions with the stationary phase can affect accuracy. Limitations include dependence on calibration standards, potential interactions with the column, and the need for appropriate solvents and sample concentrations. In practice, GPC results are most informative when combined with supplementary methods and careful method development.