Wine contains various pigments, which separate if they come into contact with the fabric.
Chromatography is a chemical method that allows the components that make up a mixture to be separated, distributing them into two phases . One of the phases is stationary (its elements are at rest), while the other is mobile (its elements move).
Separate to analyze
This technique makes it possible to separate the components for subsequent analysis. At a general level, what is done is to move the mixture on a support, causing the substances to be located in different places. Substances that remain in motion form the mobile phase , while those that separate form the stationary phase .
In addition to promoting the separation of the components, chromatography is also used to measure the proportion of each substance that makes up the mixture.
A toxicological test and the measurement of the level of water contamination are two procedures that are carried out using chromatography.
Classifications and examples
According to its characteristics , chromatography can be classified in different ways. Column chromatography , for example, allows you to separate liquids and solids, gases and solids, or gases and liquids with the stationary phase located in a column that can have various diameters and lengths. Planar chromatography , meanwhile, is carried out on a solid material, where the stationary phase is located.
We can see how chromatography works when red wine is spilled on a white tablecloth. It is common for the stain that is generated not to have a uniform tone: on the contrary, there are reddish sectors, others bluish, etc. This is because the pigments that are part of the wine experience a separation when they come into contact with the fabric of the tablecloth.
History
If we go back to the origins of chromatography, which takes us back to the mid-19th century, we will see that it was initially used with colored substances . In 1850, the analytical chemist Friedlieb Ferdinand Runge , originally from Germany, published a description of the colored areas that appeared when a coloring substance was placed on a piece of blotting paper. However, the most relevant milestone came at the beginning of the 20th century, when the botanist Mijaíl Semiónovich Tsvet , of Russian nationality, coined the term chromatography .
Shortly before, Tsvet had obtained an unprecedented achievement: working with a mixture of pigments of plant origin, he managed to divide it into a column of calcium carbonate . Another of his notable experiments was the chromatography of an egg yolk, using a complex carbohydrate called inulin. The discoveries of this important Russian scientist were not exploited until 1931, twelve years after his death. It is believed that the main reason for such lack of attention was that his work had been published in his native language and in a not very well-known print medium.
A gas chromatograph
It was then that chromatography underwent rapid growth as an analytical tool, and this was because Tsvet's research was used by other renowned scientists, Kuhn, Lederer and Winterstein , to study pigments of plant origin. In this experiment, they confirmed the Russian botanist's claims, including the fact that carotene is not a single substance but is made up of several closely related homologues. The dimensions of the columns also grew, so that the recovery of the separated components was possible.
In 1959, a chromatography technique called gel filtration appeared, developed by Porath and Flodin , which has been widely used for its effectiveness in separating substances with a high molecular weight, especially proteins. This technique has been applied in different fields, such as medicine, biology, physiology and biochemistry.