10 mM Tris–HCl + 1 mM EDTA + 0.05% Tween 20, pH 8.0 @ 25 °C
Purpose
- Tris buffers, with their pH adjusted by HCl, are often used to store DNA.
- EDTA chelates divalent cations like magnesium, which can contribute to DNA degradation.
- Tween 20 is a non-ionic detergent that reduces adsorption of DNA to plastics and improves pipetting accuracy.
- This buffer is useful for long-term storage of DNA to be used in quantitative assays, although the EDTA must be taken into consideration for any enzymatic reaction that relies on a divalent cation.
Recipe
- Final concentrations
| Tris base
|
10 mM
|
| disodium EDTA
|
1 mM
|
| Tween 20
|
0.05% (v/v)
|
| HCl
|
3.72 mM
|
- Preparing 50 mL of 1X working solution
| water
|
48.564 mL
|
| Tris base, 1 M
|
0.500 mL
|
| disodium EDTA, 0.1 M
|
0.500 mL
|
| Tween 20, 10% (v/v)
|
0.250 mL
|
| HCl, 1 N
|
0.186 mL
|
- Preparing 50 mL of 10X concentrate
| water
|
35.64 mL
|
| Tris base, 1 M
|
5.00 mL
|
| Disodium EDTA, 0.1 M
|
5.00 mL
|
| Tween 20, 10% (v/v)
|
2.50 mL
|
| HCl, 1 N
|
1.86 mL
|
Notes
- HCl titration was calculated with the Python package ionize 0.8.0.
- pH is temperature-dependent and this dependency is especially strong for Tris, so pH indicators may show a noticeably higher pH than 8.0 at temperatures lower than 25 °C.