In analytical chemistry and materials science, a method known as Gel Permeation Chromatography (GPC), also known as Size Exclusion Chromatography (SEC), is frequently used to separate and analyse macromolecules according to their molecular weight and size.

The foundation of Gel permeation chromatography is the idea that smaller molecules would get caught in the pores of the gel matrix while bigger molecules will move swiftly through it. By passing a mobile phase—typically a solvent—through a packed column of porous particles that are made to exclude specific molecules based on their size, the separation is accomplished.

The interaction between the molecules of various sizes and the gel matrix when the sample is put into the column causes the mixture to separate into its component parts to differing degrees. A detector, such as a refractive index or UV-Vis detector, can then be used to analyse the separated components and provide data on their molecular weight, size, and concentration.

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