So let's suppose this is our test tube that contains that protein number one that we wanted to actually isolate in the first place. So we can see ion exchange chromatography is actually only helpful if there is a big difference between the net charges on our protein. We cannot use ion exchange chromatography to purify proteins. If all the proteins in our mixture have the same exact type of net charge. For example, if all the proteins have a net neutral charge, then that means none of them will be attracted to those charged beads. And so what that means is the rate at which they actually move along our column will be exactly the same.