The term “chromatography” covers a wide variety of separation techniques, each fine-tuned to the needs of the application. . So, what is chromatography used for? Most chromatography procedures accomplish one or both of two goals: identification or purification. Identification seeks to answer two questions: “What is it?” and “How much is there?”. Purification involves isolating a single component from a mixture and preserving it for further use.
Unknown substances can often be characterized by running them through a chromatography system, which can match the resultant data against a data library of known chemicals. A classic example of this is in forensic science, allowing for fast and easy testing of confiscated drugs and other contraband. Chromatography identification also aids in environmental testing. Several EpA methods site chromatography procedures to identify the type and level of pollution in soil or water. In another instance, unknown or novel compounds can also be characterized with the help of chromatography separation. Once isolated, the compound is further analyzed and its structure clarified.
The results of chromatography can be seen outside the laboratory as well, on the nutrition label located on the back of many products sold in the United States. Nutrition labels are regularly generated using chromatographic methods which can detect everything from the amount of sugar in a cookie to the concentration of alcohol in beer.
In addition, the type of detector connected to the chromatography system helps with the identification process. Liquid chromatography (LC) typically uses flow-through UV spectroscopy as a detection method, while gas chromatography (GC) makes use of a flame ionization detector or thermionic specific detector. More recently, as the cost of technology has become more affordable, an increasing number of both LC and GC systems are being coupled with a mass spectrometer, a powerful tool used for identification-focused testing.
Using chromatography as a means of purification is especially common in biotechnology industries, such as when a cell has produced a compound that needs extraction. Immunological antibodies are often isolated by passing them through a chromatography channel containing their antigen. In other instances, proteins can be separated and collected based on size, polarity, or their bonding affinity with a selected ligand. Often these kinds of separations are particularly useful in the creation of vaccines, allowing scientists to isolate an immunoreactive protein around which they can design the vaccination.
Once an end goal has been decided, the specific components of a chromatography system fall into place. Different columns, mobile phases, and detectors are known to excel at performing certain separations, identifications, and purifications. This allows for tremendous flexibility when creating a chromatography procedure, while affording numerous options to fine-tune methods and achieve desired separation results.
Learn more about Chromatography: What is Chromatography and How it Does it Work?