Elution

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Elution is a term used in analytical chemistry to describe the emergence of chemicals from the column of a chromatograph. As they elute, the chemicals typically flow into a detector. Predicting and controlling the order of elution is a key aspect of column chromatographic methods.

The material emerging from the column is sometimes known as the eluate. The eluent is the carrier that moves the chemicals through the column. In liquid chromatography, the eluent is the liquid solvent; in gas chromatography, it is the carrier gas.^[1]

The mobile phase is a closely related term. The mobile phase specifically includes the analytes/solutes passing through the column, while the eluent is only the carrier.

The elution time of a solute is the time between the start of the separation (the time at which the solute enters the column) and the time at which the solute elutes. In the same way, the elution volume is the volume of eluent required to cause elution. Under standard conditions for a known mix of solutes in a certain technique, the elution volume may be enough information to identify solutes. For instance, a mixture of amino acids may be separated by ion-exchange chromatography. Under a particular set of conditions, the amino acids will elute in the same order and at the same elution volume.

[edit] References

• Brown, Phillis (2001). Advances in chromatography. CRC Press, 36. ISBN 0824705092. 

[edit] See also

• Desorption
• Gradient elution in high performance liquid chromatography

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