An ion exchange chromatography column containing an ion exchange stationary phase, the ion exchange stationary phase comprising: a) a charged substrate; b) a plurality of first particles each including first ion exchange groups and the first particles being ionically bound to the charged substrate, the first particles having a first ion exchange group density; and c) a plurality of second particles each including second ion exchange groups and the second particles being ionically bound to the charged substrate, the second particles having a second ion exchange group density, wherein the first ion exchange group density is greater than the second ion exchange group density, in which the first ion exchange groups and the second ion exchange groups both have a net charge of a same polarity, wherein the ion exchange chromatography column has a number of zones connected in series, the number of the zones ranging from about two to about ten, each zone comprising: i) an inlet zone; and ii) an outlet zone; wherein a distance from the inlet zone to the inlet of the chromatography column is less than a distance from the outlet zone to the inlet of the chromatography column, and a distance from the outlet zone to the outlet of the chromatography column is less than a distance from the inlet zone to the outlet of the chromatography column, wherein the first particles are bound to the charged substrate at an initial first particle concentration at the inlet zone and a concentration of the first particles bound to the charged substrate decreases linearly from the inlet zone towards the outlet zone to form a final first particle concentration bound to the charged substrate at the outlet zone, wherein the second particles are bound to the charged substrate at an initial second particle concentration at the inlet zone and a concentration of the second particles bound to the charged substrate increases linearly from the inlet zone towards the outlet zone to form a final second particle concentration bound to the charged substrate at the outlet zone. a) a charged substrate; b) a plurality of first particles each including first ion exchange groups and the first particles being ionically bound to the charged substrate, the first particles having a first ion exchange group density; and c) a plurality of second particles each including second ion exchange groups and the second particles being ionically bound to the charged substrate, the second particles having a second ion exchange group density, wherein the first ion exchange group density is greater than the second ion exchange group density, in which the first ion exchange groups and the second ion exchange groups both have a net charge of a same polarity, i) an inlet zone; and ii) an outlet zone; wherein a distance from the inlet zone to the inlet of the chromatography column is less than a distance from the outlet zone to the inlet of the chromatography column, and a distance from the outlet zone to the outlet of the chromatography column is less than a distance from the inlet zone to the outlet of the chromatography column, wherein the first particles are bound to the charged substrate at an initial first particle concentration at the inlet zone and a concentration of the first particles bound to the charged substrate decreases linearly from the inlet zone towards the outlet zone to form a final first particle concentration bound to the charged substrate at the outlet zone, wherein the second particles are bound to the charged substrate at an initial second particle concentration at the inlet zone and a concentration of the second particles bound to the charged substrate increases linearly from the inlet zone towards the outlet zone to form a final second particle concentration bound to the charged substrate at the outlet zone. <EOS>