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10 mM TrisHCl + 1 mM EDTA + 0.05% Tween 20, pH 8.0 @ 25 °C


  • 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.


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


  • 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.
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