The fraction of interest is dried and dissolved in the start mobile or mobile / stationary or stationary phase as required, and the new normal phase step gradient run. Usually adequate resolution is obtained by this two dimensional CCC. This approach can easily be modified and enhanced by adding a fifth solvent for enhanced selectivity. The author is presently researching two-dimensional CCC and two-dimensional CCC / Prep HPLC.
Collaboration with other researchers on these novel topics is always welcome.
It is believed the later orthogonal techniques will have considerable merit, as generic CCC gradients can separate complex natural products etc without fear of expensive Prep HPLC column poisoning, into predictable polarity fractions. The relatively low complexity CCC fractions of known polarity can then be easily resolved into individual constituents by chromatographers who will invariably have more experience in HPLC than CCC. The chromatographer will also have the added advantage of having far less loading to put onto the preparative HPLC column, therefore greatly reducing time and cost.