Tris HCl is a product that is primarily useful for simplifying the process of making Tris buffer solutions and also making them more reproducibly. By mixing appropriate quantities of Tris Base and Tris HCl, stock buffers of various pHs may be prepared. Thus there is no need to use HCl or NaOH to adjust the pH. This avoids titration "overshoot", where too much of acid is added and then some NaOH has to be added, resulting in ionic strength variability. Tables of the appropriate amounts of Tris Base and Tris HCl to add are here:

http://www.sigmaaldrich.com/Graphics/Supelco/objects/4800/4709.pdf

as well as in some paper versions of the Sigma Catalog. These tables also indicate the pH of the solutions at various temperatures--and this may also be useful, since the pH of your solution adjusted with NaOH or HCl at room temperature will not be the same if your working temperature is 37C or 4C.

Tris (as a pure compound usually supplied) is a base and its aqueous solutions are alcaline. It is not a buffer sensu stricto. To acquire a buffering capacity it sould be in equilibrium with the corresponding acid which is the protonated form of Tris. Traditionally, protonation of Tris is accomplished by addition of HCl. pH of the solution decreases to the desired value and the resulting Tris-HCl solution is what we commonly call Tris buffer.

Hi Himanshi,

First of all you need to know that a buffer normally comprises of a strong base and a weak acid or vice-versa. In case of tris buffers, the buffer actually is Tris-Cl or Tris-HCl. tris is the basic component while acidic component is provided by HCl.

Hope this helps, good luck

Tris is a base where as to this base Hcl is added u get Tris-Hcl buffer.

No big difference in between two, only pH is different. you can use both after adjusting pH of your solution.

If you use tris-base you have to add Hcl.Tris-Hcl is commercially available

Tris HCl is a product that is primarily useful for simplifying the process of making Tris buffer solutions and also making them more reproducibly. By mixing appropriate quantities of Tris Base and Tris HCl, stock buffers of various pHs may be prepared. Thus there is no need to use HCl or NaOH to adjust the pH. This avoids titration "overshoot", where too much of acid is added and then some NaOH has to be added, resulting in ionic strength variability. Tables of the appropriate amounts of Tris Base and Tris HCl to add are here:

http://www.sigmaaldrich.com/Graphics/Supelco/objects/4800/4709.pdf

as well as in some paper versions of the Sigma Catalog. These tables also indicate the pH of the solutions at various temperatures--and this may also be useful, since the pH of your solution adjusted with NaOH or HCl at room temperature will not be the same if your working temperature is 37C or 4C.

are tris Cl and tris HCl are same?

i think it is just the usage of PH dependent buffer solution. HCl makes the Tris PH value under 7. I hope this could help....

For Tris-base you add HCl for adjusting pH

You can calculte how to prepare tris hcl from tris base here:

http://www.cytographica.com/lab/HHTris.html

Dear experts , what i observed that when i used Tris-base to prepare TAE/TBE buffer, the resulting pH was around 8.5, however when i used Tris-HCL the resulting pH was below 4.0.

In order to decrease the pH i used to add HCL and the TAE/TBE buffer works well.

However using Tris-HCl (pH 4.0) i need to add NaOH . when i check this buffer for electrophoresis , it gives very low voltage ( even not able to adjust by adjustable power pack) .

Can anyone suggest me some solution for the above problem 

@Jamsheed Javid

"it gives very low voltage"   This may be because your power supply has an "amperage" limiting feature.  When you adjusted with NaOH, you added much more sodium ion to the solution, so at the same voltage, you are getting much more current.  Did you monitor the current (amps)?  For a fixed voltage, the current is a function of the ion concentration, so if there are more ions present, the current (amps) will be higher.  If your power supply is "amp-limited", you can only adjust the voltage up to the point where the amperage is maximal.  After that, no adjustment will increase the voltage and the current will remain at the maximum value.  And since higher current also means higher heat and higher heat will melt your gel, you don't want to run at higher amps anyway.  

Actually, the best solution for agarose gel electropheresis is not to use Tris "buffer" at all, but rather a simple "electroconductive medium" described in the attached papers.

A simple recipe for a 20XSB stock useful for most RNA and DNA applications, and requiring no further pH adjustment is:

For 4 liters 20X SB stock

NaOH   32 gram

Boric Acid  200 gram

Tap distilled/deionized water to 4 liter

Thank you David.

How do I adjust the pH of Tris-HCl to 8.8, if I mix Tris-HCl directly with DI water, instead of Tris base and HCl ?

SB Buffer is easy to prepare and works better than TAE and TBE. 

SB buffer Composition-20X (1L)

NaOH- 8.0g

Boric acid - 50 grams

Mix properly and use 1X as working Buffer.

Thank you, Dr. David for your valuable suggestion. 

How to prepare a series of buffers with pH values ranging from 2 to 12 

 in bis-tris buffer. Plz help me

I happened upon this thread quite by accident - but, in case you are looking for a universal buffering system with a wide range I propose to consider the attached.

Table from: Medham, J.; Denny, R.C.; Barnes, J.D.; Thomas, M (2000). Vogel's textbook of quantitative chemical analysis (5th. Ed. ed.). Harlow: Pearson Education. ISBN 0 582 22628 7. Appendix 5

Can anyone of you provide tris-tricine protocol.

Tris-glycine buffer is the tris base and glycine mixed together with adjusted pH

How do i make 1M Tris-HCl buffer pH=8.0

inTris-base you have to add HCl to bring down its pH to 8, but inTris Hcl you have to add NaOH to bring pH to 8 and to have tris buffer at pH 8.

I actually tried mix Tris-Hcl and Tris base to make 1.5M Tris buffer with pH of 8.8 and found out that when the ratio is 1:4，the pH is around 8.94, I used HCk to bring it down to 8.8. so I guess it's somewhere between 1:3--1:4, I will try next time and rewrite this answer.

Dan Zhang

The ratio formulas are given here:

https://www.sigmaaldrich.com/Graphics/Supelco/objects/4800/4709.pdf

The indicated weights are for fully dessicated reagents. So if your results don't agree, it may be because the reagents are not completely dry. Note that there are also temperature and concentration effects on the pH of Tris solutions. It may be that your mix which read as pH 8.94 as the concentrated 1.5 M solution would read as a lower pH if you diluted some of it to 0.05 M and then read the pH. In general, I think the mixing tables are very reliable predictors of working pH conditions, while adding extra HCl and/or NaOH is potentially more problematic because that will definitely change the ionic strength and may add a source of variability in different batches of stock buffers.

David F. Barker

Thanks for your advice!

I noticed the ratio formulas you put in the other answer and it's awesome. But I need it to be 1.5M so I used the 1.5M Tris base to mix with the 1.5M Tris.HCl to adjust pH value. I monitored pH value while mixing them. And when pH was around 8.9, it changed really slow so I decided to bring it down with HCl. I am luck there's no overshoot. I guess it's fine to use HCl but NaOH is definitely not appropriate.

Tris-HCl is just Tris base with an equivalent of HCl present for each molecule of Tris. So, it's essentially a version of Tris that has had its pH adjusted downwards before it even hits solution.