The values of the second dissociation constant, pK2, and related thermodynamic quantities of [N-(2-acetamido)-2-aminoethanesulfonic acid] (ACES) have already been reported over the temperature range 5 to 55 °C including 37 °C. This paper reports the paH values of four chloride ion free buffer solutions and eight buffer solutions with I=0.16 mol⋅kg−1, matching closely that of the physiological sample. Conventional paH values for all twelve buffer solutions from 5 to 55 °C are reported. The residual liquid-junction potential correction for two widely used temperatures, 25 and 37 °C, has been made. The flowing-junction calomel cell method has been utilized to measure Ej, the liquid-junction potential. The operational pH values for four buffer solutions at 25 and 37 °C are calculated using the physiological phosphate buffer standard based on the NBS/NIST convention. These solutions are recommended as pH standards in the pH range of 6.8 to 7.2 for physiological fluids.

中文翻译：

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用于两性离子化合物生理 pH 值的缓冲标准液，ACES，5 至 55 °C

[N-(2-乙酰氨基)-2-氨基乙磺酸] (ACES) 的第二解离常数 pK2 和相关热力学量的值已在 5 至 55 °C 的温度范围内（包括 37 °C）报告。本文报告了四种无氯离子缓冲溶液和八种 I=0.16 mol⋅kg-1 缓冲溶液的 paH 值，与生理样品的 paH 值非常匹配。报告了所有 12 种缓冲溶液从 5 到 55 °C 的常规 paH 值。已经对两个广泛使用的温度 25 和 37°C 进行了残余液结电位校正。流动结甘汞电池法已被用于测量 Ej，即液体结电位。四种缓冲溶液在 25 和 37 °C 下的操作 pH 值是使用基于 NBS/NIST 惯例的生理磷酸盐缓冲液标准计算的。建议将这些溶液用作生理液体 pH 值范围为 6.8 至 7.2 的 pH 值标准。