Chromatography is a method of separating mixtures complex widely used along different branches of science . It employs a set of techniques based on the principle of selective retention to separate the components of a mixture in a high state of purity, or to identify them in a mixture and determine their exact proportion .
In this way, chromatography consists of the exposure of a specific mixture to a specific support ( gas , paper, a neutral liquid , etc.) in order to take advantage of the differences in the adsorption speed of each component of the mixture, identifying them from of the color spectrum that the mixture throws in time.
The adsorption ( not absorption ) is the coefficient of adhesion of the mixture to the surface of the support, and according to the difference in the reaction speeds of the components of the mixture, these may be effectively separated or their percentage may be measured in any case. of concentration.
This separation process occurs in two phases:
- Static phase . The mixture is applied to a specific support and prepared for the measurement.
- Mobile phase . Another substance is moved on the support, to allow its reaction with the components of the mixture and that the difference in the speed of reaction separates them.
In this way, some substances will tend to move and others to stay, according to their respective natures. This can be carried out using aesthetic and mobile phases of different conditions: liquid, solid and gaseous .
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Examples of chromatography
- Spilling wine on a white tablecloth . When the wine dries in contact with the air, the different substances that compose it will color the white of the fabric in a different color , allowing to identify them when it would normally be impossible.
- In blood tests . The chromatography of blood samples is often done in order to separate and identify substances contained in it , normally imperceptible, from the color they reflect on a support or subjected to a specific light. Such is the case of some drug or some specific substance, such as alcohol.
- In a urine test . Urine, even more than blood, is a mixture of various compounds, whose presence or absence reveals the functioning of the organism. Therefore, a chromatographic separation can be performed to look for unusual residues , such as blood, salts, glucose or drugs.
- Review of crime scenes . As in the movies: fabrics, fibers, fabrics or other supports are taken to observe the separation by adhesion of different substances , such as semen or blood, which at first sight could go unnoticed.
- Health checks of food . Since the reaction of the food is known to be subjected to a chromatographic spectrum, it can be observed if there is in them some kind of improper substance or product of microbial agents from a small sample .
- Verification of pollution levels . Whether in air or water, the reaction of dissolved and imperceptible substances can be measured from a small sample, using a specific support that allows to distinguish between the compounds , allowing the water to dry, for example.
- Complex examinations of microbiology . This technique is widely used to combat diseases such as Ebola, for example, because in this case it allows the distinction between more and less effective antibodies in the face of the deadly disease.
- Petrochemical applications . Chromatography is useful in the process of separating petroleum hydrocarbons and transforming them into various refined materials, which have extremely dissimilar and observable properties and adhesions.
- Checking fires . To determine whether or not they were triggered, residue chromatography is often used to demonstrate the presence of unexpected substances whose reactivity is different from the rest , such as certain fossil fuels .
- To separate inks . Since the inks are composed of various pigments in a liquid medium, it is possible to separate these pigments by chromatography and show the differences between each one. It is, in fact, a common experiment when explaining this technique, using colored markers.
- Detection of radioactivity . Since radioactive elements have activities and emission rates different from those of ordinary matter, they can often be identified using this technique in the laboratory, exposing the material to substances that show the change in reaction speed .
- To determine the purity of a substance . In the industry, high purity materials are often required, especially gases (whose volatility makes it difficult) and a mechanism to evaluate it is the detection by chromatography of residues of other substances , based on the use of a liquid static phase.
- Study of the wines . In the detection of monovarietal wines, chromatography is often used to find out if they are mixed with other strains, since these will present different detectable characteristics in the presence of a different static medium.
- Control of industrial distilled spirits . By means of gas phase chromatography, the basic quality components present in the liquor (ethanol, methanol, acetaldehyde, acetal, etc.) can be identified and quantified , thus allowing a responsible administration of said compounds.
- Quality studies of olive oils . Chromatography is essential in the review and classification of olive oil, since it yields a study of the fatty profile, acidity and peroxide value present in the mixture.