We want to use a four-stage countercurrent extractor to separate two growth hormones present as part of an aqueous protein concentrate. The activity of each hormone in the feed solution is a nominal value of 1. We add phosphates to this concentrate, and extract with a polyethylene glycol solution which forms a second immiscible aqueous phase. The hormones partition between these phases with values of K equal to 6.0 and 8.0, respectively, where

K = [activity in polyethylene glycol solution] / [activity in phosphate solution]

We want to investigate the recovery and product purity possible with this extraction.

(a) In one series of experiments, we use a phosphate feed of 50 kg/hr and a polyethylene glycol feed of 10 kg/hr. What is the percent recovery and extract purity in this case?