Chromatography is a method of separating complex mixtures in order to analyze it. It is quickly replacing many of the more traditional techniques of sample identification and purification. How does chromatography work? A mixture goes into the chromatography process and the different parts go through the system at different rates. The difference in the speeds causes the separation of the different components of the compound.
In Chromatography there's the mobile phase and the stationary phase. The stationary phase doesn't move while the mobile phase does. As the mobile phase moves through the stationary phase, it picks up the components to be tested. At different times in the stationary phase, the different compounds are going to stop moving with the mobile phase. Thus, the particles are separated. This applies to all different types of chromatography. In paper and thin-layer chromatography the mobile phase is the solvent. The stationary phase in paper chromatography is the piece of paper that is being used. In thin-layer chromatography the stationary phase is the thin-layer cell. In both of these types of chromatography the solvent moves through the stationary phase.
There are four different types of chromatography. They are liquid chromatography, gas chromatography, thin-layer chromatography, and paper chromatography.
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Liquid chromatography is used in the real world to test rivers and lakes for pollution. It is used to analyze metal ions and organic compounds in solutions. .
Gas chromatography is used in the real world in airports to detect bombs and is used often in forensics. It also is used to analyze blood found at a crime scene and to analyze fibers on a body. In GC helium is used to move the mixture through a column of absorbent material.
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Thin-layer chromatography uses the absorbent material on plastic plates or glass. This is a simple and a quick method to check the purity of an organic compound.