Chromatografija

Chromatografija is a family of analytical techniques used to separate components of a mixture based on how they distribute between two phases: a stationary phase and a mobile phase. The name derives from Greek words for color and writing, reflecting early pigment separations. In essence, components interact differently with the stationary phase and therefore migrate at different speeds as the mobile phase passes through.

The stationary phase is a solid or a liquid supported on a solid, while the mobile phase is a gas or liquid that moves through the system. Separation depends on distribution coefficients, adsorption, partitioning, and chemical interactions with the stationary phase. Efficiency is often described by factors such as retention, selectivity, and the number of theoretical plates.

Major forms include gas chromatography (GC), where the mobile phase is an inert gas and the compounds are typically volatile; liquid chromatography (LC), especially high-performance LC (HPLC) or ultra-performance LC (UPLC), where a liquid mobile phase is pumped under high pressure through a column; and planar chromatography, such as thin-layer chromatography (TLC). Other specialized forms include ion-exchange and affinity chromatography.

Detectors such as UV-Vis, refractive index, fluorescence, or mass spectrometry are used to detect the separated substances. Practically, chromatografija is widely used for purity assessment, quantitative analysis, and structure elucidation in chemistry, biochemistry, medicine, environmental science, and food testing.

History: The technique was first developed by Mikhail S. Tsvet in 1903 for the separation of plant pigments. The term chromatography was coined by him, and the method evolved from column and planar formats to modern high-performance systems that enable rapid, sensitive separations.