The choice of gradient solvent in reverse phase HPLC is relatively easy, most chromatographers using either a water : methanol or a water : acetonitrile gradient with or without buffering. It would be relatively rare in HPLC to use multiple solvent gradients such as water : methanol : acetonitrile : THF and variation of the relative percentages of the solvents ( other than the water to organic ratio ) is almost unheard of in HPLC. The situation is not so simplistic in HSCCC gradients as almost any immiscible solvent combinations can be used in the gradient, and 3, 4 or 5 + different solvents may be utilized, with on some occasions an additional solvent(s) being phased in part way through the gradient.
The effectiveness of gradient HSCCC with a Quattro CCC is shown in Slides 9, Slide 10, Slide 11 and Slide 12.
Slides 9 describes the context of the inter-comparison of gradient HSCCC to Flash Chromatography.