Arginine leucine lysine and valine are all amino acids

Question

Arginine, Leucine, Lysine, and Valine are all amino acids. Lysine and Arginine are both under the category of charged polar amino acids, where they exhibit a positive charge. Leucine and Valine are both uncharged non-polar amino acids, and, as such, are hydrophobic.

• What would happen to a separation of amino acids if the solution pH was changed to pH 10 or 3? 

• Could this help to separate and identify amino acids that are similarly charged at pH 7?