Editing Paper chromatography (section)

{{Short description|Separation of chemicals, often colored, on paper}}
{{Refimprove|date=February 2008}}
{{Infobox chemical analysis
| name = Paper chromatography 
| image =Chromatography_tank.png
| caption = paper chromatography
| acronym = PC
| classification =[[Chromatography]]
| analytes = chromatography is a technique used for separation of the parts of a mixture of either gas or liquid solution
| manufacturers = 
| related = [[Thin layer chromatography]]
| hyphenated = 
}}
'''Paper chromatography''' is an [[analytical chemistry|analytical]] method used to separate colored chemicals or substances. It can also be used for colorless chemicals that can be located by a stain or other visualisation method after separation.<ref name=britannica>{{Cite news|url=https://www.britannica.com/science/paper-chromatography|title=Paper chromatography {{!}} chemistry|work=Encyclopedia Britannica|access-date=2018-06-01|language=en}}</ref> It is now primarily used as a teaching tool, having been replaced in the [[laboratory]] by other chromatography methods such as [[thin-layer chromatography]] (TLC).

This analytic method has three components, a mobile phase, stationary phase and a support medium (the paper). The mobile phase is generally a non-polar organic solvent in which the sample is dissolved. The stationary phase consists of (polar) water molecules that were incorporated into the paper when it was manufactured. The mobile phase travels up the stationary phase by [[capillary action]], carrying the sample with it. The difference between [[Thin-layer chromatography|TLC]] and paper chromatography is that the stationary phase in TLC is a layer of adsorbent (usually [[silica gel]], or [[aluminium oxide]]), and the stationary phase in paper chromatography is less absorbent paper.

A paper chromatography variant, [[two-dimensional chromatography]], involves using two solvents and rotating the paper 90° in between. This is useful for separating complex mixtures of compounds having similar polarity, for example, [[amino acids]].