Theory of Countercurrent Chromatography
A. General Principles of CCC
- Theory of CCC - Equations that help to understand the method
B. A Glossary of CCC
At present, the terminology of counter-current chromotographic techniques, as documented in the scientific literature, is inconsistent and sometimes confusing. Appropriate IUPAC definitions are currently being established.
- CC
- Stands for "Counter-Current", which is also spelled "countercurrent".
- CCD
- Craig's Counter-Current Distribution was a breakthrough in separtion science and became very popular in the 1940. CCD machines that occupied whole rooms were capable of handling liters of solvents and consisted of up to several hundred partition elements that automated the manual partitioning of samples in separatory funnels. For a historic review of Craig's contribution to Science see this article in JBC Centennial Classics Series.
- CCC
- The term "Counter-Current Chromatography" has hostorically been used for equipment developed in the laboratory of Dr. Yoichiro Ito of NIH (Bethesda, MD). Ranging from the early development of the droplet (DCCC, two commercial instrumental implementations) and rotation locular (RLCCC, one commercial instrumental implementation) to the centrifugal multi-layer (MLCCC) and high-speed (HSCCC) instruments. The latter have been developed into a number of commercially available instruments that are based on the coil planet centrifuge principle and lack a rotating seal. They make use of centrifugal force for phase mixing and phase separation. Historically, the acronym CCC refers to hydrodynamic methods of counter-current chromatography.
- CPC
- Another way to enhance centrifugal-force (counter-)current flow emerges from revolution around only one axis and the use of rotating seals. Thus, centrifugal partition chromatography is comparable to droplet CCC. Compared to CCC, CPC instruments are generally operated at higher flow rates and higher back pressures. Historically, the acronym CPC refers to hydrostatic methods of counter-current chromatography.
Acronymology - Some Words About Confusion and Some Confusion About Words
Unfortunately, some acronyms have been used for different experimental setups:
- CPC
- Major use: centrigual partition chromatography; other uses: coil planet centrifuge used in HSCCC, centrifugal precipitation chromatography.
C. Principles of HSCCC
C1. Flow-through Centrifuge Types for HSCCC
Several designs of centrifuges have been evaluated for their ability to permit stationary phase retention and continuous elution without rotary seals.
Figure: Search for high-speed CCC centrifuges
