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

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 paH 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 m1 = 0.04 mol · kg−1, m2 = 0.08 mol · kg−1, m3 = 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.

► This work reports pH values of MOPS buffer.
► Liquid junction potential correction is applied.
► These values will be used by clinical and biomedical scientists.
► The pH values lie within 6.8 to 7.5.