Store vial at -20° C or below prior to opening. To minimize loss of volume, dilute 1:10 by adding 225 µL of the buffer stated above directly to the vial. Recap, mix thoroughly and briefly centrifuge to collect the volume at the bottom of the vial. Use this intermediate dilution when calculating final dilutions as recommended above. Store the vial at -20°C or below after dilution. Avoid cycles of freezing and thawing