Buffer standards for the physiological pH of the zwitterionic compound of 3-( N-morpholino)propanesulfonic acid (MOPS) from T = (278.15 to 328.15) K

Abstract

This paper reports the pH values of five NaCl-free buffer solutions and 11 buffer compositions containing NaCl at I = 0.16 mol · kg −1. Conventional p a H values are reported for 16 buffer solutions with and without NaCl salt. The operational pH values have been calculated for five buffer solutions and are recommended as pH standards at T = (298.15 and 310.15) K after correcting the liquid junction potentials. For buffer solutions with the composition m 1 = 0.04 mol · kg −1, m 2 = 0.08 mol · kg −1, m 3 = 0.08 mol · kg −1 at I = 0.16 mol · kg −1, the pH at 310.15 K is 7.269, which is close to 7.407, the pH of blood serum. It is recommended as a pH standard for biological specimens.