a. Preheat buffer B2 for 5 minutes at 70C.

b. Pipet buffer B2 into buffer B1, pipetting up and down to mix the buffers completely. A 200µl blood sample needs 200µl of buffer B3 consisting of 160µl of buffer B1 and 40µl of buffer B2.

c. The RNase (heat treated), must be added to buffer B4 before use. After the addition of the RNase the buffer B4 should be stored at 4C.

d. The proteinase K must be dissolved in sterile water (1250µl) and should be stored at 4C.

e. Add 48ml ethanol (96%) to the buffer B5 before use.

f. The buffers B3 and B5 must be stored at room temperature.

g. If the volume of the blood sample is less than 200µl add the appropriate volume of PBS buffer to the sample. For the preparation of PBS dissolve 8g NaCl, 0.2g KCl, 1.44g Na2HPO4 and 0.24g of KH2HPO4 in 800ml of distilled water. Adjust the pH to 7.4 with HCl. Add H2O to 1 liter. Dispense the solution into aliquots and sterilize them. Store at room temperature.

Standard Protocol

1. Prepare a 70C waterbath.

2. Equilibrate the blood sample to room temperature.

3. Make sure that buffers B3, B4 and B5 and the proteinase K solution have been prepared according to the remarks above.

4. Pipet the blood sample into a 1.5ml centrifuge tube. If the volume of the sample is less than 200µl add the appropriate volume of PBS buffer (see remarks above).

5. Add 25µl proteinase K solution and 200µl buffer B3 to the sample and vortex the mixture until any pellet is dissolved.

6. Incubate the mixture at 70C for 10 minutes.

7. Cool the mixture to room temperature, add 100µl of buffer B4 (including RNase), vortex and incubate the sample 5 minutes at room temperature.

8. Add 210µl isopropanol (or ethanol) to the sample and vortex again.

9. Place the NucleoSpin tube into a 2ml centrifuge tube. Apply the sample to the NucleoSpin tube and centrifuge 1 minute at 6000xg (RT). If the sample is not drawn through the matrix completely repeat the centrifugation step. Discard the filtrate.

10. Add 500µl buffer B5 (including ethanol) to the spin cup and centrifuge 1 minute at 6000xg (RT). Discard the flowthrough. Repeat this washing step.

11. After the two washing steps with buffer B5 discard the flowthrough. Place the NucleoSpin tube into the centrifuge tube again and centrifuge for 1 minute at 6000xg (RT) in order to completely remove buffer B5.

12. Place the NucleoSpin tube in a clean 1.5ml centrifuge tube and elute the DNA with 200µl preheated (70C) 10mM Tris/HCl, pH 9. Centrifuge for 1 minute at 6000xg (RT).

Having specific problems? Please refer to the Nucleobond AX Trouble Shooting Guide.

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