Column chromatography



Column chromatography in chemical compounds from mixtures of compounds. It is often used for preparative applications on scales from micrograms up to kilograms.

 

The classical preparative chromatography column is a glass tube with a diameter from 5 to 50 mm and a height of 50 cm to 1 m with a tap at the bottom. A slurry is prepared of the separating funnel is put on top of the column.

The individual components are retained by the stationary phase differently and separate from each other while they are running at different speeds through the column with the eluent. At the end of the column they elute one at a time. During the entire chromatography process the eluent is collected in a series of UV lamp) can be seen through the glass wall as moving bands.

Stationary phase (adsorbent)

The stationary phase or adsorbent in column chromatography is a solid. The most common stationary phase for column chromatography is affinity chromatography or expanded bed adsorption (EBA). The stationary phases are usually finely ground powders or gels and/or are microporous for an increased surface, though in EBA a fluidized bed is used.

Mobile phase (eluent)

The mobile phase or thin layer chromatography (TLC) with the same stationary phase.

A faster argon) to push the solvent through the column (flash column chromatography).

Systems

Automated flash chromatography systems attempt to minimize human involvement in the purification process. Automated systems may include components normally found on HPLC systems (gradient pump, sample injection apparatus, UV detector) and a fraction collector to collect the eluent.

The software controlling an automated system will coordinate the components and help the user to find the resulting purified material within the fraction collector. The software will also store results from the process for archival or later recall purposes.

A representative example of column chromatography as part of an undergraduate laboratory exercise is the separation of three components (out of 28) in the oil of spearmint: ethyl acetate.

See also

References

  1. ^ Isolation of Three Components from Spearmint Oil: An Exercise in Column and Thin-Layer Chromatography Davies, Don R.; Johnson, Todd M. J. Chem. Educ. 2007 84 318. Abstract
 
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