Salting out
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Salting out is a technique in which a homogeneous mixture of two liquids can be separated using a salt.
The same term (also called salt-induced precipitation or precipitation crystallization) is also used for the technique of purification for proteins, as well as preventing protein denaturation due to excessively diluted samples during experiments. In this case, it is an effect based on the electrolyte–non-electrolyte interaction, in which the non-electrolyte could be less soluble at high salt concentrations.
General
In cases where a salt has a strong affinity for one of the two liquids but is virtually insoluble in the other, addition of that salt can cause separate layers of the two liquids to form, allowing them to be extracted from the mixture. Examples of this include the salting out of isopropanol/water mixtures with sodium chloride and/or sodium hydroxide, and the salting out of ethanol/water mixtures with potassium carbonate. A liquid thus obtained from salting out typically needs to be distilled or otherwise cleaned of any possible solutes that may have found their way in during the process.
