Buffer Standards for the Physiological pH of the Zwitterionic Compound, DIPSO, from 5 to 55 A°C

The values of the second dissociation constant, pK (2), and related thermodynamic quantities of 3-[N,N-bis (2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (DIPSO) have already been reported over the temperature range 5 to 55 A degrees C including 37 A degrees C. This paper reports the pH values of four NaCl-free buffer solutions and four buffer composition containing NaCl salt at I=0.16 mola <...kg(-1). Conventional pa (H) values are reported for all eight buffer solutions. The operational pH values have been calculated for four buffer solutions recommended as pH standards, at 25 and 37 A degrees C after correcting the liquid junction potentials with the flowing junction cell.