Chromatographic techniques are a broad range of physical methods used to separate or analyse mixtures constituted by several types of compounds. The components to be separated are distributed between two phases; a stationary phase bed and a mobile phase that percolates through the stationary bed. When a sample having a mixture of several components enters in a chromatographic medium, the different compounds are flushed through the system at different rates. The differential rates of migration occur as the mixture moves through the stationary phase providing, therefore, separation. The smaller the affinity a particular solute has for the stationary phase the shorter will be the time spending inside a column during a elution process.

Chromatography is a very special separation process for a multitude of reasons. First of all, it can separate the constituents of complex mixtures with great precision, even very similar components, such as isomers that may only vary by a single double bond. It can also purify basically any soluble or volatile substance if the right stationary phase material, carrier fluid and operating conditions are optimised. Second, chromatography can be used to separate delicate products since the conditions under which it is performed are not typically severe. Nowadays, very sophisticated equipments are used for the application of the several chromatographic techniques, with emphasis to gas (GC) and liquid (HPLC) chromatography constituted by appropriate columns and other indispensable devices, namely by sensitive and selective detectors for the analytes under study, for which all the chromatographic process is automated and controlled by suitable software, as is exemplified in figure 1.