Buffer Standards for the Biochemical pH of 3-(N-morpholino)-2-hydroxypropanesulfonic Acid from (278.15 to 328.15) K.
The values of the second dissociation constant pK(2) and related thermodynamic quantities of the ampholyte 3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO) have been previously determined at temperatures from (278.15 to 328.15) K. In this study, the pH values of two buffer solutions without NaCl and three buffer solutions with NaCl having ionic strengths (I = 0.16 mol·kg(-1)) similar to those in blood plasma, have been evaluated at 12 temperatures from (278.15 to 328.15) K using an extended form of the Debye-Hückel equation, since the Bates-Guggenheim convention is valid up to I = 0.1 mol·kg(-1). The liquid junction potentials (E(j)) between the buffer solutions of MOPSO and saturated KCl solution of the calomel electrode at (298.15 and 310.15) K have been estimated by measurement with a flowing junction cell. These values of E(j) have been used to ascertain the operational pH values at (298.15 and 310.15) K. Three buffer solutions of MOPSO are recommended as useful reference solutions for pH measurements in saline media of ionic strength I = 0.16 mol·kg(-1).
Roy
Lakshmi N
LN
Hoffman Department of Chemistry, Drury University, Springfield, MO 65802.
Roy
Rabindra N
RN
Denton
Cole E
CE
Lenoue
Sean R
SR
Roy
Chandra N
CN
Ashkenazi
Shahaf
S
Fuge
Michael S
MS
Wollen
Joshua T
JT
Stegner
Jessica M
JM
Allen
Kathleen A
KA
Harmon
Meagan A
MA