ChromPure is our trade name for highly purified proteins from the serum of non-immunized animals.Physical State: Sterile-filtered liquid Storage: Store at 2-8°C under sterile conditions. Prepare working dilution fresh each day.Expiration date: one year from date of receipt. However, the expiration date may be extended if the product is stored according to the recommendation and the test results are acceptable for its intended use.Purity:Based on immunoelectrophoresis at an antigen concentration of 20 mg/ml, the pattern of precipitation against goat anti-guinea pig whole serum is the same as that against goat anti-guinea pig IgG, Fc fragment specific. Preservative:None