Credo si dica così...Opposta alla "stationary phase" (fase stazionaria)

http://en.wikipedia.org/wiki/Countercurrent_chromatography
f a less dense mobile phase is used it will rise through the stationary phase, this is called ascending mode. The eluent from one column is transferred to another; the more columns that are used, the more theoretical plates can be achieved. The disadvantage of DCCC is that flow rates are low, and poor mixing is achieved, which makes this technique both time-consuming and inefficient.