Author(s)

Rabindra N. Roy, Lakshmi N. Roy, Blake M. Bodendorfer, Zachary M. Downs, Stephen D. Rocchio, Joshua T. Wollen, Jessica M. Stegner, Isaac B. Henson, Nicholas W. Grove, Lauren A. Dieterman

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Hoffman Department of Chemistry, Drury University, Springfield, USA.

The authors have undertaken the determination of pH values for one buffer solution of TES without NaCl and nine buffer solutions with NaCl yielding an ionic strength I = mol.kg^-1. similar to that of blood. These buffer solutions have been evaluated in the temperature range of 5℃ to 55℃ using an extended version of the Debye-Hückel equation. The pH values are reported using 1) the Debye-Hückel extension of the Bates-Guggenheim convention in the tempera- ture range 5℃ to 55℃ and 2) with and without liquid junction correction at 25℃ and 37℃. These TES buffer solutions are recommended as secondary standard references for pH measurements in the range of pH 7.2 to 7.5 for physiological application with an ionic strength of I = 0.16 mol.kg^-1.

Ionic Strength; Liquid Junction Potentials; Second Dissociation Constant; Buffer Solutions; Activity Coefficients

R. Roy, L. Roy, B. Bodendorfer, Z. Downs, S. Rocchio, J. Wollen, J. Stegner, I. Henson, N. Grove and L. Dieterman, "Buffer Standards for the Biochemical pH of the Zwitterionic Buffer N-Tris-(Hydroxymethyl) Methyl-2-Aminoethanesulfonic Acid (TES) from 5℃ to 55℃," Open Journal of Physical Chemistry, Vol. 2 No. 1, 2012, pp. 41-46. doi: 10.4236/ojpc.2012.21006.