TRIS [tris(hydroxymethyl)aminomethane] is proposed as a new buffer with the advantages of being nontoxic and having only one conjugated acid. Moreover, it is well-established in biochemical applications, has good solubility in water (550 g/L), and is reasonably priced. Comparable micromixing experiments in a TRIS buffer and a borate buffer led to similar segregation indices with respective micromixing times. Furthermore, TRIS was successfully transferred to experiments in viscous glycerin–water solution. Comparable micromixing experiments with sulfuric acid in TRIS highlight the importance of including the ionic strength dependency of the second dissociation constant of sulfuric acid to obtain similar micromixing times. Micromixing experiments become thereby independent of the acid choice. The application and limitation of the phosphate buffer were investigated in more detail where comparable experiments have shown that HPO₄^2– is the only species to be considered in micromixing time calculations when the HPO₄^2–/H₂PO₄^– ratio is over 20. It is shown whether and how the effect of the ionic strength on the pK_a2 value of phosphoric acid should be considered when micromixing experiments are conducted in a phosphate buffer as it is close to the dismutation pH* of iodine.

中文翻译：

---

Villermaux-Dushman 反应缓冲液选择的进展

TRIS [三(羟甲基)氨基甲烷]被提议作为一种新的缓冲液，具有无毒和只有一种共轭酸的优点。此外，它在生化应用中得到了广泛认可，在水中具有良好的溶解度（550 g/L），并且价格合理。在 TRIS 缓冲液和硼酸盐缓冲液中进行可比较的微混合实验导致了相似的分离指数和各自的微混合时间。此外，TRIS 成功地转移到粘性甘油水溶液的实验中。在 TRIS 中用硫酸进行的可比微混合实验强调了包括硫酸的第二解离常数的离子强度依赖性以获得相似的微混合时间的重要性。微混合实验因此变得独立于酸的选择。_{当 HPO 4} ^2– /H ₂ PO ₄ ^{–比值超过 20 时，} ₄ ^2–是微混合时间计算中唯一需要考虑的物质。它显示了离子强度是否以及如何影响 p Ka2_值在磷酸盐缓冲液中进行微量混合实验时应考虑磷酸，因为它接近碘的歧化 pH*。