Abstract: A method for separating a feed mixture comprising at least two solutes by an intermittent multi column chromatography process with a basic step N performed in a predetermined switching time period. Basic step N comprises two sub steps which are carried out sequentially according to a predetermined step ratio. In sub step one inlet ports and outlet ports are open, a desorbent and a feed mixture enters upstream of a first and a third section. A first outlet stream comprising the desorbent and at least one solute is withdrawn downstream of the first section a second outlet stream comprising the desorbent and at least a further solute is withdrawn downstream of a the third section. In sub step two inlet ports and outlet ports are closed, a fluid stream comprising the desorbent part of the feed mixture circulates through three sections in a closed loop.