Posted 20 April 2012 - 11:28 AM
Make very sure you are spinning the columns dry, after dumping the wash from the collection tube. Small amounts of wash will inhibit the elution of the product from the column. This is especially an issue with small elution volumes. You could elute a second time, which would work even if the first elution merely diluted the ethanol left in the column. You need to clean up after PCR and before digestion, but you do not need to clean up after digestion if you can heat kill your restriction enzymes. Choose enzymes that can be heat killed.