Extraction Technologies for Medicinal and Aromatic ... - Capacity4Dev

13 COUNTER-CURRENT CHROMATOGRAPHY
Counter-current Chromatography (CCC) is a unique form of liquid
partition chromatography which utilizes a separation column free of solid support
matrix. Because of this support-free system, the method provides an important
advantage over other chromatographic methods by eliminating various complications
such as adsorptive loss and deactivation of samples and contamination.
During the 1970s, the method was steadily improved by accelerating the
separation speed and efficiency. In the early 1980s, an epoch-making advance
was achieved by the advent of high-speed CCC (HSCCC) which can yield highly
efficient separation in a short period of time. Because of its high performance,
the recent research and development of the CCC technology have been almost
entirely focused on HSCCC, high performance centrifugal partition chromatography
(HPCPC), and fast centrifugal partition chromatography (FCPC).
Recent developments in CCC instruments, explaining the use
of CCC for better separation and their applications in the separation of bioactive
natural products from plants, are discussed in this paper.
13.2 Principles and Development of Countercurrent
Chromatography
Anyone conversant with the technique of liquid-liquid extraction
(using a separatory funnel) can readily understand the principles of Countercurrent
Chromatography (CCC), where separation is based on the partition of
solutes between two immiscible liquid phases. In CCC, one of the two phases
is retained in the column and is called the stationary phase. The second phase,
which is called the mobile phase, percolates through the stationary one.
13.2.1 Liquid-liquid Extraction
Liquid-liquid extraction is a simple means of separating large
quantities of materials, using a minimum of solvent. After dissolving the
sample in a two-phase solvent system (in a separatory funnel), the steps in
performing liquid-liquid extractions are as follows:
• Shake vigorously to thoroughly mix the two phases.
• Allow the mixture to settle into two phases.
• Separate the phases from each other.
These steps are crucial to achieve the separation of sample components.
The chief disadvantage of liquid-liquid extraction is that it provides
only one plate of separation in the original sense.
Accordingly, either this single-step separation must be designed
to suit one’s needs, or multiple liquid-liquid extractions must be used
to increase the separation.
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