Phenyl-Sepharose resin consists of a phenyl group attached to a matrix of agarose. Suppose you need to use this chromatographic method to separate a mixture of polypeptides consisting of polyalanine, polyserine, polytryptophan and polylysine. Would you apply these polypeptides in a buffer containing high ionic strength or low ionic strength? What buffer would you choose (choose from one of “Good’s buffers” (find a list online)? How would you elute the polypeptides, and what would be the order of elution?