Measurement of Physiological pH in Biological Specimens

今天常用的酸碱度刻度是用来产生酸度函数的精确差值的 参考标准与其他性质类似但酸度不同的介质之间的差异。这些 标准是离子强度接近0.1m的稀缓冲液；也就是说，稀释度要高得多。 比大多数有生理价值的基质(i=0.16m)都要高。对其他解决方案的结果进行可靠的解释 可以预期的是具有类似成分的，但其他的，如那些含有更高数量的 中性盐可能是可疑的。尽管涵盖大多数生理介质的pH范围的标准是 目前，很难选择与其他解决方案紧密匹配的参考解决方案 受关注的未知媒体的属性。 对于i=0.1m以上的离子强度，每个人都是‘各自为政’和结果的差异(计算 单离子活度系数)很可能出现在不同的实验室之间。中国的长期目标是 研究是为了消除目前各种惯例的限制(贝茨-古根海姆，有效期至I= 0.1m)通过使用Pitzer离子相互作用方法来(I)计算所需的单个离子活度 离子强度i=0.16m时标准缓冲液pH值测定中的离子物种，类似 与生物样本(血液、血浆等)中发现的相同；(Ii)将它们与基于 更简单的惯例；以及(Iii)评估在生理介质(i=0.16m)中通过变化产生的影响 在中性盐含量的标准或感兴趣的介质。如果成功，则分配 与生理介质性质紧密匹配的标准参比溶液的PH值应为 有可能，从而改善这些实验pH数据的可靠性和意义 媒体。在这方面，12种新的生化缓冲化合物(HEPPS，AMPSO，HEPPSO，PIPESO， CAPS、CAPSO、MOPSO、ACES、CHES、MES、TRICINE和PIPES)将被调查。最后，这可能会 建立适用于所有情况(不同离子强度、混合物、 等)。因此，匹泽公约和提法符合这些要求。 在过去，约600名学生(现有助学金约70名学生)曾受到 这个机会和许多人都被激励去从事科学和医学事业。因此，它是 计划再次向学生提供这个机会，让他们更全面、更专注、更 和值得称道的研究提案。

The scale of pH in common use today is designed to yield accurate differences of an acidity function between a standard of reference and other media of a comparable nature but differing acidity. These standards are dilute buffer solutions with typically ionic strengths near 0.1 m; that is, considerably more dilute than most media (I = 0.16 m) of physiological interest. Reliable interpretation of the results for other solutions of comparable composition can be expected, but others, such as those containing higher quantities of neutral salt may be suspect. Although standards covering the range of pH of most physiological media are available, it is presently difficult to choose a reference solution that matches closely in respect to other properties of the unknown media of concern. For ionic strength above I = 0.1 m, everyone is 'on his own' and differences of the results (calculation of the single ion activity coefficient) between various laboratories are likely to occur. A long-term goal of the research is to remove the present restriction of various conventions (the Bates-Guggenheim, valid up to I = 0.1 m) by use of the Pitzer ion-interaction approach to (i) calculate the required single ion activity of a single ionic species in the determination of pH values for the standard buffers at an ionic strength I = 0.16 m, similar to that found in biological specimens (blood, plasma, etc.); to (ii)compare them with those based on the simpler conventions; and to (iii) evaluate the effect produced in physiological media (I = 0.16m) by variations in the neutral salt content of either the standard or the medium of interest. If successful, the assignment of pH values to standard reference solutions matching closely the properties of physiological media should be possible, with a consequent improvement in the reliability and meaning of experimental pH data for these media. In this connection, twelve new biochemical buffer compounds (HEPPS, AMPSO, HEPPSO, PIPESO, CAPS, CAPSO, MOPSO, ACES, CHES, MES, TRICINE, and PIPES) will be investigated. Finally, this may establish a self-consistent, unified pH scale that is applicable to all cases (different ionic strengths, mixtures, etc.). Thus, the Pitzer convention and formulation fit the bills. In the past, some 600 students (about seventy students for the existing grant) have been challenged by this opportunity and many have been motivated toward careers in science and medicine. Consequently, it is planned that this opportunity will be offered to students once more to work on a more integrated, focused, and meritorious research proposal.