|MadSci Network: Chemistry|
Dear Mary: Chromatography is one of the most used analytical chemistry techniques. But before I go ahead and give you examples I will say that there are two main types of chromatography: Liquid Chromatography (LC) and Gas Chromatograpy (GC). LC is based on the movement of a liquid (mobile phase) through a column (or bed) made of a solid material (solid Phase) (example paper chromatography is a form of LC). Each compound in a mixture has a different affinity (preference) for the solid and liquid phases. As they move through the solid phase they start to separate because some of them like to spend more time on the solid phase and therefore move slower than compounds that like to send more time on the liquid phase. This is why you can separate colours in a ink sample using paper chromatography. Similarly, GC is based on a mobile phase, this time a gas, and a solid or thick liquid phase (kind of gummy phase) coated on a solid phase. GC is used to separate compounds that can be made volatile, that is to say, compounds that can be turned into vapour; while LC is mainly used for compounds that are not easily evaporated. This does not mean that you can't use GC to do some of the compounds you would do by LC. LC and GC are used in the following workplaces: Hospitals: to separate drugs of abuse in blood samples, to separate and find out how much medicinal drugs and other compounds in blood, salive, urine Environmental Laboratories: to separate and determine pesticides and otehr contaminants in waters, soils, and animals (such as find out what and how much contaminants are present in drinking water) Forensic Laboratories: To analyse samples coming from a crime scene In Industries to determine the components present in pretroleum and oils to determine dyes and additive in foods to determine pesticides and other additives in foods and the list goes on. I am a chromatographer and right now we are using LC couple with a mass spectrometric detector (if you want to know what is a mass spectrometric detector let me know) to determined three different kinds of drugs in plasma (a part of blood) from donors. Hope this helps
Try the links in the MadSci Library for more information on Chemistry.