Comparison of Partition Chromatographic Methods

In a direct comparison of RLCC and DCCC (Fig. 2.21), two molluscicidal iridoid glycosides were isolated from Olea europaea (220). The RLCC isolation was considerably faster than the DCCC (3 days compared to 5) and used about the same quantity of eluent. On the other hand, the previously-mentioned separation of chromomycins took only 4.5 hours with CPC compared to 2.5 days with RLCC (52). 

A survey of the literature readily leads to the conclusion that coil-CCC, RLCC, and CPC can accommodate a broader range of solute types than DCCC (330, 331). The former methods can be applied for the isolation of both natural products and biopolymers. There are no reports, however, about DCCC isolations of higher molecular-weight biopolymers. 

While competing and somewhat conflicting claims are made for the coil-CCC methods and the DCCC, it seems safe to project that the range of solvents compatible with each instrument, as well as the time factor necessary to complete the chromatography will remain comparable. DCCC suffers somewhat from the limitation of solvent selectivity, since the mobile phase must form droplets or at least pass through the stationary phase in a droplet-like stream to avoid stationary phase displacement, and a limitation of solvent selectivity has been mentioned for the coil-CCC due to the tendency of the stationary phase to gradually be transported from the apparatus. 

Countercurrent chromatography is playing an increasingly valuable role in modern isolation methods, complementing both the conventional adsorption 

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