The staining dye can be removed from DNA with traditional ethanol precipitation, PCR clean up kits, or the gel extraction kits. The ethanol precipitation method can follow conventional molecular cloning or follow the listed protocol. Ethanol precipitation.
A. Measure the volume of the DNA sample.
B. Add 1/10 volume of 3M sodium acetate, pH 5.2,(final concentration of 0.3 M) - The pH value of 3M sodium acetate must be adjusted with acetate not with HCl.
C. Mix well.
D. Add 2 to 2.5 volumes of cold 100% ethanol (calculated after salt addition).
E. Mix well.
F. Place on ice or at -20 °C for >20 minutes.
G. Spin at maximum speed in a microfuge for 10-15 min.
H. Carefully decant supernatant.
I. Add 1 mL 70% ethanol. Rinse and spin briefly. Carefully decant supernatant.
J. Air dry or briefly vacuum dry pellet.
K. Re-suspend pellet in the appropriate volume of TE, Tris buffer or water.