R. Roy, L. N. Roy, Bennett J. Tabor
Oct 1, 2004
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0
Influential Citations
6
Citations
Journal
Journal of Solution Chemistry
Abstract
The values of the second dissociation constant, pK2, and related thermodynamic quantities of 4-(N-morpholino)butanesulfonic acid (MOBS) and N-tris(hydroxymethyl)-4-aminobutanesulfonic acid (TABS) have already been reported over the temperature range 5–55°C including 37{°}C. This paper reports the pH values of twelve equimolal buffer solutions at designated pH (s) with the following compositions: (a) mixtures of MOBS (0.05 mol-kg−1) + NaMOBS (0.05 mol-kg−1); (b) MOBS (0.08 mol-kg−1) + NaMOBS (0.08 mol-kg−1); (c) MOBS (0.08 mol-kg−1) + NaMOBS (0.08 mol-kg−1) + NaCl (0.08 mol-kg−1); (d) TABS (0.05 mol-kg−1) + NaTABS (0.05 mol-kg−1); and (e) TABS (0.08 mol-kg−1) + NaTABS (0.08 mol-kg−1); and (f) TABS (0.08 mol-kg−1) + NaTABS (0.08 mol-kg−1) + NaCl (0.08 mol-kg−1). Two buffer solutions have ionic strengths I= 0.05 mol-kg−1, another two have I=0.08 mol-kg−1, and the remaining two buffer solutions have I= 0.16 mol-kg−1, which is close to that of the clinical fluids (blood serum). These buffers have been recommended as a useful pH standard for the measurements of physiological solutions. Conventional pH values of all six buffer solutions from 5–55°C, as well as those obtained from the liquid junction potential correction at 25 and 37{°}C have been calculated. The flowing-junction calomel cell has been utilized to measure Ej, the liquid junction potential.