1.Agarose electrophoresis, cut the specific electrophoresis band with a knife and put it into EP tube, weigh the agarose band.

2.Add 400 μl of binding buffer every 100mg, put it into EP tube oscillator, incubate at 45 ℃ ~ 55 ℃ and shake until all agarose is dissolved (about 5 minutes).

3.Take out the purification column, transfer the above solution to the column, place it at room temperature for 2 minutes, centrifugate it at 8000rpm for 1 minute, discard the liquid in EP tube, and put the purification column back into EP tube.

4.Add 500 μl of wash buffer to the column and centrifugate at 8000rpm for 1 minute. Solution in abandoned pipe.

5.Repeat the operation of 4 steps for 1 time, and finally put the purification column into EP tube at 10000rpm for centrifugation for 30 seconds to remove trace wash buffer.

6.Put the purification column into a new EP tube. Add 30-40 μl H₂O or elusion buffer to the center of the purification column membrane, place at 37 ℃ or 50 ℃ for 2 minutes, centrifuge at 10000 rpm for 1 minute to elute DNA, and store the DNA solution in EP tube at -20 ℃.

7.Note: if you want to purify the DNA solution directly without electrophoresis, you only need to add 400 μl binding buffer according to the amount of 100 μl solution in step 2, and the rest steps remain the same.