PH BUFFERS FOR SEA-WATER MEDIA BASED ON THE TOTAL HYDROGEN-ION CONCENTRATION SCALE

Published e.m.f. values measured using the cell Pt(s)\H-2(g,P(o))\BH+ and B in synthetic sea water\AgCl(s)\Ag(s)\Pt(s) where p(o) = 101.325 kPa, and BH+ and B are the conjugate acid-base pairs of 2-aminopyridine, 2-amino-2-hydroxymethyl-1,3-propanediol (tris), tetrahydro-1,4-isoxazine (morpholine), and 2-amino-2-methyl-1,3-propanediol (bis), have been re-evaluated to assign pH values based on the ''total'' hydrogen ion concentration scale to equimolal (m = 0.04 mol kg-1) buffer solutions based on these compounds. These pH values are consistent with the best available equilibrium constants for acid-base processes in sea water and such pH buffers can be used as pH calibration standards to measure accurate values for oceanic pH on the ''total'' hydrogen ion pH scale. In addition, the published e.m.f. results for these various amine bases have been used to calculate their respective acidity constants on this pH scale.