Molecular weight of Tris base 121.1
Molecular weight of Tris HCl 157.6
Can we use Tris HCl instead of Tris base for preparation of CTAB buffer?
If yes how much amount we will take for prepare 1M TrisHCl solution?
You can use Tris-HCl instead of Tris of the same molarity. However, you will have to adjust pH to the required value by neutralizing HCl with some NaOH or the other base.
Hi there,
If you use Tris-HCl, once pH is adjusted, the solution will contain other components than Tris-base, Tris+ and Cl- (ie. Na+ if NaOH has been used) so your buffer will not be exactly a Tris-HCl buffer. Tris-HCl buffer is always obtained from the acidification of Tris-Base by HCl.
Hi, sure you can. I did all my CTAB buffers only with Tris HCl @ 250 mM and never had any problems.
So according to the primary source of Tris you use, you will get 2 different buffer solutions with two different ionic strengths which may be a problem if ionic strength is an issue for your experiments. Starting from Tris-Base will give you the lower ionic strength whereas starting from Tris-HCl will automatically generate appreciable NaCl (or KCl) in your final solution...
Dr. Dominique Liger is right of course. Indeed, Tris buffers of the same molarity and pH, but prepared from Tris base + HCl or from Tris-HCl + NaOH will have different composition and ionic strength. In practice it is of little concern for most applications since NaCl is an inactive salt. But this difference should be taken into consideration in cases where ionic strength is important. For example, in DNA melting or DNA-ligand binding experiments. I think it is not important for the use of CTAB buffer (moreover a very high NaCl concenmtration is present in CTAB anyway).
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