Roy Rabindra N, Roy Lakshmi N, Ashkenazi Shahaf, Wollen Joshua T, Dunseth Craig D, Fuge Michael S, Durden Jared L, Roy Chandra N, Hughes Hannah M, Morris Brett T, Cline Kevin L
J Solution Chem. 2009 Apr 1;38(4):449-458. doi: 10.1007/s10953-009-9378-3.
The values of the second dissociation constant, pK(2) of N-(2-hydroxyethyl) piperazine-N'-2-ethanesulfonic acid (HEPES) have been reported at 12 temperatures over the temperature range 5 to 55 degrees C, including 37 degrees C. This paper reports the results for the pa(H) of eight isotonic saline buffer solutions with an I = 0.16 molkg(-1) including compositions: (a) HEPES (0.01 molkg(-1)) + NaHEPES (0.01 molkg(-1)) + NaCl (0.15 molkg(-1)); (b) HEPES (0.02 molkg(-1)) + NaHEPES (0.02 molkg(-1)) + NaCl (0.14 molkg(-1)); (c) HEPES (0.03 molkg(-1)) + NaHEPES (0.03 molkg(-1)) + NaCl (0.13 molkg(-1)); (d) HEPES (0.04 molkg(-1)) + NaHEPES (0.04 molkg(-1)) + NaCl (0.12 molkg(-1)); (e) HEPES (0.05 molkg(-1)) + NaHEPES (0.05 molkg(-1)) + NaCl (0.11 molkg(-1)); (f) HEPES (0.06 molkg(-1)) + NaHEPES (0.06 molkg(-1)) + NaCl (0.10 molkg(-1)); (g) HEPES (0.07 molkg(-1)) + NaHEPES (0.07 molkg(-1)) + NaCl (0.09 molkg(-1)); and (h) HEPES (0.08 molkg(-1)) + NaHEPES (0.08 molkg(-1)) + NaCl (0.08 molkg(-1)). Conventional pa(H) values, for all eight buffer solutions from 5 to 55 degrees C have been calculated. The operational pH values with liquid junction corrections, at 25 and 37 degrees C have been determined based on the NBS/NIST standard between the physiological phosphate standard and four buffer solutions. These are recommended as pH standards for physiological fluids in the range of pH 7.3 to 7.5 at I = 0.16 molkg(-1).
N-（2-羟乙基）哌嗪-N'-2-乙磺酸（HEPES）的第二解离常数pK(2)的值已在5至55摄氏度（包括37摄氏度）的12个温度下报告。本文报告了8种等渗盐缓冲溶液在I = 0.16 mol·kg⁻¹时的pa(H)结果，包括以下组成：(a) HEPES（0.01 mol·kg⁻¹）+ NaHEPES（0.01 mol·kg⁻¹）+ NaCl（0.15 mol·kg⁻¹）；(b) HEPES（0.02 mol·kg⁻¹）+ NaHEPES（0.02 mol·kg⁻¹）+ NaCl（0.14 mol·kg⁻¹）；(c) HEPES（0.03 mol·kg⁻¹）+ NaHEPES（0.03 mol·kg⁻¹）+ NaCl（0.13 mol·kg⁻¹）；(d) HEPES（0.04 mol·kg⁻¹）+ NaHEPES（0.04 mol·kg⁻¹）+ NaCl（0.12 mol·kg⁻¹）；(e) HEPES（0.05 mol·kg⁻¹）+ NaHEPES（0.05 mol·kg⁻¹）+ NaCl（0.11 mol·kg⁻¹）；(f) HEPES（0.06 mol·kg⁻¹）+ NaHEPES（0.06 mol·kg⁻¹）+ NaCl（0.10 mol·kg⁻¹）；(g) HEPES（0.07 mol·kg⁻¹）+ NaHEPES（0.07 mol·kg⁻¹）+ NaCl（0.09 mol·kg⁻¹）；以及(h) HEPES（0.08 mol·kg⁻¹）+ NaHEPES（0.08 mol·kg⁻¹）+ NaCl（0.08 mol·kg⁻¹）。已计算出所有8种缓冲溶液在5至55摄氏度时的常规pa(H)值。基于生理磷酸盐标准与四种缓冲溶液之间的NBS/NIST标准，已确定了25和37摄氏度时带有液接界校正的操作pH值。这些被推荐为I = 0.16 mol·kg⁻¹时pH值在7.3至7.5范围内生理流体的pH标准。
