To the purification by oxidization method,either H 2O 2 quantity is decreased to 1.5%(48 hours) or oxidization time shorted to 12 hours(3.0% H 2O 2) with adds of 0.005% YNB 99 1 separately.

• 12 0 USP u/ mg以上的粗品在 p H中性下直接使用0 .；0 5%25的 YNB99- 1即可。