Question

Miniprep DNA Wash Buffer (PE) contains: 10 mM Tris-HCl pH 7.5 and 80% ethanol (v/v)

Answer the following:

a. You are asked to prepare 80 mL of DNA Wash Buffer (PE). How many mL of 100% ethanol should be added, then the total volume adjusted to the 80 mL final volume?

Answer 1

For 80mL preparation

V1N1 = V2N2

V1 =Initial volume of Ethanol or unknown (X)    N1 = Initial Concentration or Stock solution or Ethanol (100%)

V2 =Final volume of solution (80mL)    N2 = Final Concentration of Ethanol in the solution (80%)*

        X * 100 = 80ml * 80

        X = 80 * 80 / 100

       X = 64 mL of ethanol is required from the 100% of ethanol.