# How much Tris do I need to get pH neutral glycine - (Jan/18/2008 )

I have eluted my protein with 1ml of pH 2 glycine and I want to bring it back to pH neutral before denaturing and running on a gel. I have Tris at pH 8.8, so how do I go about calculating how much of that I need to add to bring it to pH neutral. (I could use highe pH tris as well if that helps - ideally I want to add a very small volume).

-thewhorule2002-

you can add 100µL of 1M Tris pH 7.5.

-SMH-

QUOTE (SMH @ Jan 18 2008, 02:26 PM)
you can add 100µL of 1M Tris pH 7.5.

Surely 1ml of pH2 50mM glycine plus 100ul of pH 7.5 1M tris would still be acidic?

If not could you let me know how you worked it out?

Thanks

-thewhorule2002-

the procedure i used was to add 1/20th fraction volume of 1M tris pH 8 (for glycine pH 2.5) to the tube, then drip the fraction into the buffer "cushion".

-mdfenko-

QUOTE (mdfenko @ Jan 18 2008, 07:15 PM)
the procedure i used was to add 1/20th fraction volume of 1M tris pH 8 (for glycine pH 2.5) to the tube, then drip the fraction into the buffer "cushion".

Can I ask if anyone knows how to do the calculation to know that this will give a final solution that is pH 7.4?

Thanks, any help will be greatly appreciated

-thewhorule2002-

QUOTE (thewhorule2002 @ Jan 23 2008, 04:27 AM)
QUOTE (mdfenko @ Jan 18 2008, 07:15 PM)
the procedure i used was to add 1/20th fraction volume of 1M tris pH 8 (for glycine pH 2.5) to the tube, then drip the fraction into the buffer "cushion".

Can I ask if anyone knows how to do the calculation to know that this will give a final solution that is pH 7.4?

Thanks, any help will be greatly appreciated

all I know is that I use Glycine pH2,5 and add 100µL of Tris 1M pH 7.5 or 8 to 1ml aliquot. I never tested the final pH, you can try it out though before eluting your protein.

I don't know how to do the calculation.

-SMH-

QUOTE (thewhorule2002 @ Jan 23 2008, 07:27 AM)
Can I ask if anyone knows how to do the calculation to know that this will give a final solution that is pH 7.4?

Thanks, any help will be greatly appreciated

instead of calculating, why not actually determine it.

take the buffer that you will use to elute the column and fill a tube with as much as you will find in your fractions. then add 1M tris until you reach your preferred pH. put that amount into each tube.

-mdfenko-