chromatographique

Chromatographic (chromatographique is the French form) refers to chromatography, a family of techniques used to separate components of a mixture based on differential partitioning between a stationary phase and a mobile phase. The name comes from Greek chroma (color) and graphein (to write); historically many separations were observed as color bands, but today the term applies to a wide range of detection methods and materials.

Principle: A sample is carried by the mobile phase through or over a stationary phase. Components interact differently with the two phases, causing them to migrate at different rates and separate over time. Key metrics include retention time, capacity factor (k′), selectivity, and resolution, which together describe the quality and speed of a separation.

Main forms: Planar chromatography, such as thin-layer chromatography (TLC) and paper chromatography, uses a flat stationary phase. Column chromatography passes the sample through a packed or open column and is common in preparative work. Gas chromatography (GC) employs a gaseous mobile phase for volatile compounds. High-performance liquid chromatography (HPLC) and ultra-high-performance liquid chromatography (UHPLC) use liquid mobile phases at high pressure and feature a variety of stationary phases for versatile separations.

Modes and phases: Chromatography encompasses partition (normal-phase and reversed-phase), adsorption, ion-exchange, size-exclusion, and affinity techniques. Stationary phases include silica gel, alumina, and polymeric materials; mobile phases are liquids or gases. Detectors range from UV–Vis and refractive index to fluorescence and mass spectrometry.

Applications: The method is widely used in chemistry, biochemistry, environmental analysis, pharmaceuticals, food safety, and forensics to identify, quantify, and purify components.

History: Chromatography was developed by Mikhail Tsvet in 1906, with major advances in GC and HPLC in the mid-20th century expanding its scope and commercial use.