in a free flow state and allows elution in steps is described application_number US 201113246830 A description historically the columns used in preparative chromatography are vertical cylindrical tubes packed with chromatography media intended to bind the target molecules and then elute them slowly with a buffer and collecting various fractions of the eluent the fractions containing the target molecule in its purest form are then pooled to obtain a desired degree of purification the methods of preparative chromatography are borrowed from the methods of chromatography used for analytical separation of components such as the use of high pressure to improve the separation efficiency in preparative chromatography it is the completeness of binding and the ability to elute is more important there are many complexities in operating these columns one being a long time needed to load the column with a process liquid containing a target molecule such as a protein surprisingly the fact that the target molecule will bind with the chromatography media in any environment suitable for such binding and it is not necessary to force a process liquid through a column to achieve the binding has been ignored in every current design of columns used in preparative chromatography the present invention obviates the need for long loading times and additionally introduces methods that allow step elution to purify the target molecules without the need for typical rigid columns and their associated hardware including pumps pipes controllers etc a first preferred embodiment of the invention is shown in fig1 where a flexible container 1 containing chromatography media 2 a process liquid inlet 3 a process liquid outlet 4 a.