Chromatography - uses
Chromatography (colour writing) is a chemical process used in the laboratory in which a substance mixture is separated through the different manner of distribution of its individual components in a stationary and mobile phase. Depending on the chromatographic separation process, the stationary phase consists of a solid or liquid and the mobile phase consists of a gas or liquid. The purpose of chromatography is to detect individual substances in a mixture or to determine their concentration as well as to isolate substances preventatively from a substance mixture for further processing. Chromatography is used in practice in chemistry, biology, medicine, pharmacy, environmental analysis, criminal forensics, the food or chemical industry. Examples of application: in the field of production, for example, chromatography is used to isolate or purify substances, in chemical analysis to separate mixtures into as homogeneous components as possible for the purpose of identifying or quantitatively analysing the samples. Included in our range of chromatography equipment are chromatography devices, systems and accessories for the most varied of applications in laboratories, inorganic and organic chemistry, biochemistry, microbiology, biotechnology, food chemistry or environmental chemistry.
Chromatography - basic principle and explanation of the process
Chromatography explained simply: although there are different chemical chromatography processes, the underlying principle can be illustrated relatively simply. A rapidly flowing river (water = mobile phase) usually carries material along with it (= various substances in chromatography). The rate at which this material moves depends on several factors: on the one hand on the type of material, i.e. small sand grains are transported more quickly than larger stones, and on the other hand on the nature of the river bed (= stationary phase), rough surfaces increase the friction on the material being carried along and thereby reduce the rate of transportation, and finally on the speed of the flow. Thus, if a mixture of small grains of sand and large pieces of gravel is shaken into the river, in principle all the fine-grained sand will reach a particular point first, followed by larger particles at certain intervals. In chromatography various substances in a mixture become distributed differently. In the mobile phase a liquid or gas moves past a solid or liquid stationary phase more or less quickly, as a result of which the contained substances become separated. The separation of the contained substances depends on the affinity to the stationary or mobile phase.
Chromatography - types of separation
According to the separation principle, the various types of chromatography can be classified as adsorption, distribution, ion exchanges, affinity, gel permeation or chiral chromatography. For the user in the laboratory and for selecting the devices, systems and accessories for individual chromatography requirements, a division on the basis of the mobile phase and carrier material or aggregate state of the stationary phase is more helpful.
Paper chromatography: in accordance with its separation method, paper chromatography is a type of liquid chromatography in which the solid, stationary phase is paper. Usually a paper strip is used that stands vertically in a glass container. In turn, the mobile phase as the eluent is a liquid which is moved due to capillary forces and transports the substances of the substance mixture. Paper chromatography is used in the analysis of substance mixtures.
Thin-layer chromatography: thin-layer chromatography also comes under liquid chromatography and in terms of its method functions on the basis of the same separation principle as paper chromatography. The difference in the separation method is the stationary phase which in thin-layer chromatography mostly consists of aluminium oxide, cellulose or silica gel which is very finely applied to a carrier material (aluminium foil, plastic film, glass plate) on which the substance to be investigated are subsequently separated. The advantages of this type of chromatography are its rapid run time and also the highly sensitive degree of detection.
Column chromatography: in laboratory practice column chromatography is considered as liquid chromatography. Its stationary phase mostly consists of finely pulverised silica gel or aluminium oxide which is placed in a glass tube and filled with a solvent (often cyclohexane/ethyl acetate) as the mobile phase. In principle, in this method the separated components leave the tube consecutively. Column chromatography is mainly used in the purification of preparations.
High-performance liquid chromatography: high-performance liquid chromatography (HPLC) belongs to the column chromatography group. In analysis it is the most frequently applied method of separation under high pressure.
Gas chromatography: various processes are used in gas chromatography. Both gas-solid chromatography, or the more commonly used gas-liquid chromatography are employed in the laboratory. The carrier material, such as silicone oil, is filled into a thin spiral-shaped tube and the gas mixture to be analysed flows through the spiral together with the gaseous separation gas (often nitrogen, helium or argon). At the end a detector measures the occurring temperature fluctuations. From these the components of the substances can be determined. Gas chromatography is used for the detection of gaseous or non-decomposed vaporing substances.
Chromatography - accessories
Our chromatography equipment range includes chromatography devices by reputable laboratory technology manufactures that are also reliable, safe and convenient to use. The chromatography systems also allow you to replace parts or add accessories. Depending on the model and method, you can order various chromatography components and accessories, such as different carrier materials, blotting/chromatography paper, chromatography columns, glass plates, UV light, capillary pipettes, spray heads, chromatography refrigerators and chromatography chambers and many other components.