And the technique, the method that we use to separate proteins based on the net charge is called ion exchange chromatography, or simply ion chromatography. So the setup in ion exchange chromatography is very similar to that of gel filtration chromatography. So it looks something like this. So we have two types of setups, and in each setup, we have a funnel that is placed on top of a long column, and inside that column, we have special gel beads. Now, in this particular case, the gel beads are made so that they have a positive charge. And in this case, the gel beads are made so that they have a negative charge.