Chromatography is used in many different disciplines of science to separate mixtures by flowing it over or through a material referred to as a stationary phase. The mixture that is to be separated has to be dissolved in a mobile phase liquid before it can be passed through the other material.
The mixture’s various components move at different speeds through the stationary phase. This is due to every element and molecule having a different weight. A good example of a stationary phase is a piece of paper soaked with the mobile phase, or the liquid. When the paper dries or develops, you can see the various parts of the mixture as spots. The stationary phase in chromatography can be paper, glass coated in an absorbent, or even gas. The devices used to hold the various phases come in several shapes, but are not random and each have a process tied to it. An example of one of these devices is a column chromatography bed, meaning that the stationary bed is in a tube.
In some situations, chromatography is used as a method of purification. This is referred to as preparative chromatography. Another use of chromatography is analytical chromatography. This method of separation occurs with smaller amounts of material and is used to measure analytes in a mixture. The amounts that are measured are only relative proportions, but are accurate enough for scientific testing.