Veincurrent Drops 9.6mg/ml (Ginkgoflavoneglycosides)

Countercurrent chromatography(CCC, alsocounter-current chromatography) is a form ofliquid–liquid chromatographythat uses a liquidstationary phasethat is held in place by inertia of the molecules composing the stationary phase accelerating toward the center of a centrifuge due tocentripetal forceand is used to separate, identify, and quantify the chemical components of amixture. In its broadest sense, countercurrent chromatography encompasses a collection of relatedliquid chromatographytechniques that employ twoimmiscibleliquid phases without a solid support.The two liquid phases come in contact with each other as at least one phase is pumped through acolumn, a hollow tube or a series of chambers connected with channels, which contains both phases. The resulting dynamic mixing and settling action allows the components to be separated by their respective solubilities in the two phases. A wide variety of two-phase solvent systems consisting of at least two immiscible liquids may be employed to provide the proper selectivity for the desired separation. Some types of countercurrent chromatography, such as dual flow CCC, feature a true countercurrent process where the two immiscible phases flow past each other and exit at opposite ends of the column.More often, however, one liquid acts as the stationary phase and is retained in the column while the mobile phase is pumped through it. The liquid stationary phase is held in place by gravity or inertia of the molecules composing the stationary phase accelerating toward the center of a centrifuge due tocentripetal force. An example of a gravity method is called droplet counter current chromatography (DCCC).There are two modes by which the stationary phase is retained by centripetal force:hydrostaticandhydrodynamic. In the hydrostatic method, the column is rotated about a central axis.Hydrostatic instruments are marketed under the name centrifugal partition chromatography (CPC).Hydrodynamic instruments are often marketed as high-speed or high-performance countercurrent chromatography (HSCCC and HPCCC respectively) instruments which rely on theArchimedes' screwforce in a helical coil to retain the stationary phase in the column. The components of a CCC system are similar to most liquid chromatography configurations, such ashigh-performance liquid chromatography(HPLC). One or more pumps deliver the phases to the column which is the CCC instrument itself. Samples are introduced into the column through a sample loop filled with an automated or manual syringe. The outflow is monitored with various detectors such asultraviolet–visible spectroscopyormass spectrometry. The operation of the pumps, CCC instrument, sample injection, and detection may be controlled manually or with a microprocessor.