* Logic is: each reaction had ~ 2,000 ng of plasmid (2.9 µL of 690 ng/µL) and we did 6 reactions, so 12,000 ng total. If you lost 0% on the column, you will get 12,000 ng in 30 µL, i.e. 400 ng/µL. If you lost 50% on the column, you will get 6,000 ng in 30 µL, i.e. 200 ng/µL.