Editing Chromatography (section)

===Countercurrent chromatography===
{{further|Countercurrent chromatography}}Countercurrent chromatography (CCC) is a type of liquid-liquid chromatography, where both the stationary and mobile phases are liquids and the liquid stationary phase is held stagnant by a strong centrifugal force.<ref>{{cite journal |last1=Berthod |first1=Alain |last2=Maryutina |first2=Tatyana |last3=Spivakov |first3=Boris |last4=Shpigun |first4=Oleg |last5=Sutherland |first5=Ian A. |date=2009-01-01 |title=Countercurrent chromatography in analytical chemistry (IUPAC Technical Report) |journal=Pure and Applied Chemistry |language=en |volume=81 |issue=2 |pages=355–387 |doi=10.1351/PAC-REP-08-06-05 |issn=1365-3075|doi-access=free }}</ref>

==== Hydrodynamic countercurrent chromatography (CCC) ====
The operating principle of CCC instrument requires a column consisting of an open tube coiled around a bobbin. The bobbin is rotated in a double-axis gyratory motion (a cardioid), which causes a variable gravity (G) field to act on the column during each rotation. This motion causes the column to see one partitioning step per revolution and components of the sample separate in the column due to their partitioning coefficient between the two [[Miscibility|immiscible]] liquid phases used. There are many types of CCC available today. These include HSCCC (High Speed CCC) and HPCCC (High Performance CCC). HPCCC is the latest and best-performing version of the instrumentation available currently.

==== Centrifugal partition chromatography (CPC) ====
{{Further|Centrifugal partition chromatography}}
In the CPC (centrifugal partition chromatography or hydrostatic countercurrent chromatography) instrument, the column consists of a series of cells interconnected by ducts attached to a rotor. This rotor rotates on its central axis creating the centrifugal field necessary to hold the stationary phase in place. The separation process in CPC is governed solely by the partitioning of solutes between the stationary and mobile phases, which mechanism can be easily described using the partition coefficients (''K<sub>D</sub>'') of solutes. CPC instruments are commercially available for laboratory, pilot, and industrial-scale separations with different sizes of columns ranging from some 10 milliliters to 10 liters in volume.