Gel permeation chromatography is a chromatographic technique that separates solute molecules according to their sizes. When sample solutions with different molecular sizes of solutes pass through the gel column, because the network structure inside the gel particles has molecular sieve effect, solutes with different molecular sizes will be hindered differently. Because the molecular weight is not easy to penetrate into the network, it is excluded from the particles, so the blocking effect is small. 1. Gel particles 2. Medium molecules 3. Small molecules 4. Macromolecules flow out of the chromatographic bed first, while those with small molecular weight flow out of the chromatographic bed because they can penetrate into the network diagram 1 and the schematic diagram of gel permeation chromatography, so the blocking effect is large, and then they flow out of the chromatographic bed, which can be achieved.

The key of gel chromatography is to establish liquid-solid phase equilibrium, and then separate different substances at an appropriate elution speed. High temperature is conducive to the rapid establishment of liquid-solid phase equilibrium. However, the high temperature also causes the solute to diffuse too fast in the liquid, which leads to the reduction of separation efficiency.

The purpose is to separate the mixture and obtain a certain amount of pure components, including the purification of organic synthetic products and the separation and purification of natural products.