tris or tris Hcl - (Jun/22/2006 )
hai
a very basic question. while preparing TAE or TBE for electrophoresis, should Tris base alone is to be used or can Tris-Hcl also be used?
if not what difference does this make?
a very basic question. while preparing TAE or TBE for electrophoresis, should Tris base alone is to be used or can Tris-Hcl also be used?
if not what difference does this make?
hai ,
basically the electrophoresis buffer should be at pH 7.5- 8.so inorder to make tris base which is originally at pH 11 , we add HCl to it and thus it is made tris -HCl and that is all the difference. commercially available tris HCl are having molecular weight greater the tris base and pH will be 8.
Honestly, in the two labs I've been working, we never cared about the pH of the solution. We prepared the solution with powder Tris and the acetate took care of adjusting the pH. Never had problems. 
well, I have not made TAE all the different ways and pH'd it...but I would not say that the tris doesn't matter...I will have to respectfully disagree
this is because it is not the final pH of the solution that you care about...it's the buffering capacity offered by the tris. you need to add tris in the proper proportions to the rest of the ingredients. what I mean to say, is that you can use any tris you want, as long it is the right one for the recipe you have.
I took my recipe for 50X TAE straight out of maniatis and it calls for tris-base. If you use tris-HCl then you are getting a different number of moles of tris in respect to your EDTA and your oAc. I would be concerned that the buffering capacity of the solutions would not be equal. But, please let me reiterate...I have not 'done the experiment' and tested to see how much difference there would be...perhaps it doesn't really matter in this case...but then perhaps it's like subsituting baking powder for baking soda...they're quite similar, but wow you can wreck your cookies if you don't follow the recipe as written 
if you want to use tris-hcl instead of tris-base then you have to recalculate the amount to add to maintain the proper molar concentration of tris in the final solution and will have to adjust the pH a little differently. you will, however, introduce Cl ions into your buffer (this may or not make a difference, depending on how you normally adjust your pH).
How can Tris be adjusted to desired pH with concentrated HCl. For example, I want to make 1 M Tris pH 8, so how is volume of concentrated HCl will be added to get that pH.
Second question: does pH of Tris-EDTA affect to primer quality when you dilute primer by Tris-EDTA 10:1 as normal lab doing?
tris dissolve in water to get part of it as cation and part of it as anions.
By adding HCl, you force some molecules to accept the H+ ions, balancing the pH to a lower value. The pH remains stable as the tris holds good buffering proerties.
The volume needed is depending of the molarity ofthe tris solution you have. A1MTris has strong buffering capacitiy whereas 10mM gets lower one.
you need to monitor the pH when adding HCl.