In our lab we use to separate the lysozyme using cat ionic exanger column(Mono S) in FPLC. Which is eluted using TBB and Sodium Phosphate buffer in the range of 50mM to 200mM concentration. The collected eluate was immediately neutralized with 36% hydrochloric acid to a pH of about 7.0, then dialyzed overnight against 2 l of 50 mm Na-acetate buffer , pH 5.0). Eluate was further concentrated by ultrafiltration.