of Countercurrent Chromatography
A. General Principles
B. A Glossary of
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.
- Stands for "Counter-Current",
which is also spelled "countercurrent".
- 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.
- 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.
- 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
Acronymology - Some
Words About Confusion and Some Confusion About Words
acronyms have been used for different experimental setups:
- Major use: centrigual
partition chromatography; other uses: coil planet centrifuge
used in HSCCC, centrifugal precipitation chromatography.