1. Store test kits at 2-8˚C when not in use, and do not use the kits beyond the expiration date. 2. Remove microwell sealer slightly to prevent the powder from being released from the wells. 3.Avoid direct sunlight and direct blows during testing. 4. Do not re-use pipette tips, test strips or microwells. 5. The pH value of the extract solution of corn germ meal, sprayed corn husk, corn gluten meal and some finished feed less than 5, i.e. pH<5, please adjust the pH value to 6.0-8.0 with 2.0mol/L NaOH solution, then dilute, mix, and test.