Method of purifying target molecules from one or more impurities in a clarified sample, whereby the target molecule is a protein or a mixture of two or more proteins, the method comprising the steps of a) providing at least three separation units having the same chromatography matrix which are connected so that liquid can at least flow from one separation unit to the subsequent one and from the last to the first separation unit b) feeding the sample on a first separation unit so that while the sample is loaded on this separation unit wherein the sample is at a first pH and conductivity enabling the target molecules to be bound to this separation unit, said separation unit is at least part of the loading time in fluid communication with the next separation unit so that target molecules not bound to said first separation unit can bind to the next separation unit, at the same time at least washing, eluting and reequilibrating one separation unit different from the separation unit that is being loaded and from the one that is in fluid communication with the separation unit that is being loaded c) switching the feed to the next separation unit d) feeding the sample on the next separation unit so that while the sample is being loaded on said next separation unit wherein the sample is at a first pH and conductivity enabling the target molecules to be bound to said next separation unit, said next separation unit is at least part of the loading time in fluid communication with the separation unit after the next so that target molecules not bound to said next separation unit can bind to the separation unit after the next, at the same time at least washing, eluting and/or reequilibrating one separation unit different from the separation unit that is being loaded and from the one that is in fluid communication with the separation unit that is being loaded e) repeating steps c) and d) one or more times, characterized in that the feed never stops and has a velocity above 800 cm/h and that the chromatography matrix of the separation units comprises particles with an average particle size diameter between 30 and 200 μm and with average pore diameters in the range between 50 nm and 200 nm and carries affinity ligands or ion exchange ligands. a) providing at least three separation units having the same chromatography matrix which are connected so that liquid can at least flow from one separation unit to the subsequent one and from the last to the first separation unit b) feeding the sample on a first separation unit so that while the sample is loaded on this separation unit wherein the sample is at a first pH and conductivity enabling the target molecules to be bound to this separation unit, said separation unit is at least part of the loading time in fluid communication with the next separation unit so that target molecules not bound to said first separation unit can bind to the next separation unit, at the same time at least washing, eluting and reequilibrating one separation unit different from the separation unit that is being loaded and from the one that is in fluid communication with the separation unit that is being loaded c) switching the feed to the next separation unit d) feeding the sample on the next separation unit so that while the sample is being loaded on said next separation unit wherein the sample is at a first pH and conductivity enabling the target molecules to be bound to said next separation unit, said next separation unit is at least part of the loading time in fluid communication with the separation unit after the next so that target molecules not bound to said next separation unit can bind to the separation unit after the next, at the same time at least washing, eluting and/or reequilibrating one separation unit different from the separation unit that is being loaded and from the one that is in fluid communication with the separation unit that is being loaded e) repeating steps c) and d) one or more times, characterized in that the feed never stops and has a velocity above 800 cm/h and that the chromatography matrix of the separation units comprises particles with an average particle size diameter between 30 and 200 μm and with average pore diameters in the range between 50 nm and 200 nm and carries affinity ligands or ion exchange ligands.