Add 600 µl of wash Buffer (ethanol added) into the center of the DF Column and let stand for 1 minute. Centrifuge at 14-16,000 x g for 30 seconds. Discard the flow-through and place the DF Colimn back in the 2 ml Collection Tube. Centrifuge again for 3 minutes at 14-16,000 x g to dry the column matrix.