Reversed-phase chromatography

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Reverse-phase chromatography (RPC) includes any chromatographic method that uses a a non-polar stationary phase. All of the mathematical and experimental considerations used in other chromatographic methods apply (ie separation resolution proportional to the column length and inversely proportional to the column width). Reversed-phase column chromatography is widely used in the pharmaceutical, chemical, and biochemical industry for separating molecules of small molecular weight. In more recent years RPC has been used to separate larger molecules.

[edit] Stationary Phases

Any inert non-polar substance that achieves sufficient packing can be used for reversed-phase chromatography. Common examples include larger hydrocarbons, diphenyl, and divinylbenzene.

[edit] Mobile Phase Considerations

Typically mobile phases are made of water or a polar organic compound such as acetonitrile or the lighter alcohols. Buffer solutions are used to control the protonation of functional groups. For example, a buffer of high pH will encourage elution of alcohols because they are charged in basic solutions and therefore prefer to be in the mobile phase. For the same reason, very acidic solutions encourage the elution of nitrogen containing molecules. Using multiple buffers allows for selective elution of a wide variety of chemicals.

[edit] External links

• Reversed Phase Chromatography