Chromatography is a term which can reference a variety of different ways of separating different aspects of analytes for preparative or analytical applications. Even though the nuances of everyone of type of chromatographic process vary, essentially what happens is this: an analyte or mixture containing an analyte is combined with a solvent to form a liquid or gas (or supercritical fluid in some cases) referred to as mobile phase. The mobile phase is then passed by way of a medium fixed in position called, understandably enough, the stationary phase; these components is frequently silica, but varies with regards to the form of chromatography being performed.
The differing physical or chemical properties of the constituent components of the mobile phase lead them to move through the stationary phase at different rates; an activity which separates the analyte from the other the different parts of the mobile phase. These different partition coefficients, because they are known, will be the grounds for chromatographic preparation and analysis within the laboratory. Essentially, the less affinity that your given component in the mobile phase has for your material from the stationary phase, the greater quickly it'll go through the column. It is a bit more complicated than all that, of course, but here is the general principle behind chromatography.
In preparative chromatographic applications, the idea is to separate the ingredients from the mobile phase, that are then often put to use elsewhere inside the laboratory. It may be a powerful purification process with certain materials and could be carried out in nearly any quantity as needed. Analytical applications, alternatively, are often performed using much smaller volumes of fabric, with all the chromatograph getting used use a measurement of the power aspects of the sample being tested. This technique may also be used to discover if a given analyte is actually present in a sample in any way. While their aims may vary, preparative and analytical chromatography may actually be practiced within a operation.
Probably the most familiar chromatographic testing to most people may be the columnar method, though paper (which relies upon the different rates of which materials bond with a sheet of cellulose), planar and thin layer (which both often use a sheet of glass like a substrate underneath a layer of silica or cellulose) chromatographic methods may also be common. There are in fact a variety of methods available, with some being more appropriate to specific applications or different analytes. Their state and kind of analyte to be tested for and the intent behind the separation largely see whether liquid or gas chromatography and which particular type is acceptable.
These technology is useful not just in research laboratories but you are also extensively utilized in producing chemicals and biotechnology products, where it's most commonly used like a separation and purification method. The precision that the chromatographic process permits the separation of perhaps the most complex of mixtures in which the constituents have only the minutest variation. Provided the correct solvent and the proper medium since the stationary phase, almost any mixture that is soluble can be separated by doing this, making chromatography just about the most common procedures in laboratories.