Chromatography is an analytical technique which involves the separation of a mixture of materials into individual components. Separation of a sample is achieved by the partitioning of a component via selective adsorption, using a solvent or a gas during the mobile phase, and desorption as the mixture passes over a stationary phase. Each substance contained in the test sample has a unique way to interact with both phases. Components are identified based on retention time, so substances that are very soluble during the mobile phase move quickly, and are adsorbed only slightly during the stationary phase, while those adsorbed more thoroughly move slower. The result is their separation.

Chromatographic techniques are invasive and destructive since they require the processing of the entire sample in order to obtain the necessary information. With these techniques it is possible have precise qualitative and quantitative analysis of the organic materials of artworks, such as varnishes, adhesives, oils, proteins, etc. 

There are several chromatographic techniques, such as column chromatography, paper chromatography, thin layer chromatography. The most popular chromatographic techniques are high-performance liquid chromatography (HPLC) and gas chromatography (GC).