Good* Buffer Properties

Physical properties of the Good buffers.  The maximum distance between atomic centers was measured from a 3-D model of the molecule and used as an estimate of the Stokes radius (a) of the molecule.  The same was done for weak electrolytes with known diffusion coeficients (D).  Linear regression of D vs 1/a for the weak electrolytes was used to predict the unknown Ds (E[D]) of the Good buffers.
Buffer Mr pKa atomicdist 2a [Angstroms] E [D]
MES  195.23  6.15 O7-H20 7.08  0.820 
ACES  182.19  6.90 H12-H13 10.03  0.668 
MOPS  209.26  7.15 H14-H21 10.15  0.664 
HEPES  238.30  7.55 O14-H16 11.41  0.618 
TRICINE  179.17  8.15 H13-H16 8.56  0.731 
TRIS  121.14  8.30 H11-H15 6.28  0.886 

*

Good, N. E., and Izawa, S. (1972). Hydrogen ion buffers. Methods Enzymol 24, 53-68.

Ferguson, W. J., Braunschweiger, K. I., Braunschweiger, W. R., Smith, J. R., McCormick, J. J., Wasmann, C. C., Jarvis, N. P., Bell, D. H., and Good, N. E. (1980). Hydrogen ion buffers for biological research. Anal Biochem 104, 300-10.



Last Updated on 05/13/2000
By Joseph G. Kunkel
Email: joe@bio.umass.edu