What is Separation Science?

Separation science occurs within a laboratory context, involving the detailed study and controlled separation of mixtures. Mixtures are substances made from two or more elements and compounds which have been simply mixed together. When mixtures are created, no chemical reactions take place, and no chemical bonds are formed. Subsequently, mixtures can be separated into their component parts using techniques such as distillation and evaporation.

Separation science is also referred to as “chromatography”, a term which combines the Greek words for colour (“chroma”) and writing (“graphein”). The various techniques and methods which underpin separation science inform the study of chemistry and biology, as well as engineering. Major advances in separation science have enabled biologists, chemists, pharmacists and environmentalists to make breakthroughs of their own. Genomics, drug discovery, DNA fingerprinting and ultra-trace residue analysis, for instance, would not be possible without recourse to the findings generated by separation science. 

Different types of separation science: preparative and analytical chromatography

Separation science, or chromatography, can be analytical or preparative. Analytical chromatography relies on small amounts of material and strives to measure the relative amounts of analytes in a mixture. No attempt is made to ready the material for future use.

Preparative chromatography, on the other hand, seeks to separate a mixture into usable component parts. Preparative chromatography can be done on a small scale or an industrial scale.

Separation processes

Separation processes convert mixtures into their constituent parts. Barring a handful of exceptions, almost every element and compound known to man is found in an impure – or mixed – state naturally. Before these impure substances can be put to good use, they must be separated into their constituent parts. In some instances, separation may result in a number of pure components. However, at other times, incomplete separation will suffice. Naturally occurring crude oil, for example, contains a mixture of different hydrocarbons and impurities. The refining process separates these substances into other, more valuable mixtures, such as gasoline, natural gas and chemical feedstocks. A series of separations takes place before the desired end products are considered usable.

In general, separations are based on differences in physical or chemical properties, such as shape, density, size, mass and chemical affinity. When no clear difference can be identified, multiple operations are generally performed to achieve the desired separation.

The article An Introduction into the Role of Gas Chromatography – Mass Spectrometry (GC-MS) in Metabolomic Analysis explores separation methods in more detail.