An apparatus and a method are provided for column chromatography, which provide improvements in separation resolution and detection sensitivity, comprising a chromatography column, the column having an inlet and an outlet, wherein the inlet is configured to introduce a flow of mobile phase into the column carrying a sample, whereby the sample separates into components as it advances longitudinally through the column from the inlet to the outlet carried by the mobile phase, wherein the inlet is further configured to introduce the flow of mobile phase into the column in at least two separate portions which are independently controllable, and to introduce the portions into different radial regions of the column, such that the portions flow longitudinally through the column in different radial regions. The sample preferably is contained in one of the portions, especially a central portion, in a higher concentration than in the other portion(s). Preferably the flow velocities of the portions are independently controllable.