AN EXACT DEFINITION OF TOTAL ALKALINITY AND A PROCEDURE FOR THE ESTIMATION OF ALKALINITY AND TOTAL INORGANIC CARBON FROM TITRATION DATA
AN EXACT DEFINITION OF TOTAL ALKALINITY AND A PROCEDURE FOR THE ESTIMATION OF ALKALINITY AND TOTAL INORGANIC CARBON FROM TITRATION DATA
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DOI：
10.1016/0198-0149(81)90121-7
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
DICKSON, AG
中科院分区：
文献类型：
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作者：
DICKSON, AG
天然水样的总(或滴定)碱度可以被认为是溶液相对于任意定义的零质子水平的质子赤字的量度。因此，明确地将任何特定的酸碱体系纳入碱度定义的问题就是决定将哪种形式指定为质子的零能级的问题。建议将其定义为具有离解常数K>；10-4.5(在25度)的酸。C和零离子强度)被认为是质子给体；这些碱是由含K的弱酸形成的。10-4.5被认为是质子受体。提出了一种从电位滴定数据估算海水样品总碱度(AT)和总无机碳(CT)的非线性最小二乘法。与当前使用的精化GRAN函数相比，该方法在概念上有了重大改进。可对AT和CT估计值的统计不确定度进行估计。由于不需要超过碱度当量点进行滴定，因此也有可能加快滴定速度。
The total (or titration) alkalinity of a natural water sample can be regarded as a measure of the proton deficit of the solution relative to an arbitrarily defined zero level of protons. The problem of unambiguously incorporating any particular acid-base system into the definition of alkalinity is thus the one of deciding which form to specify as the zero level of protons. It is proposed that it be defined so that acids with a dissociation constant K > 10-4.5 (at 25.degree. C and zero ionic strength) are considered as proton donors; those bases formed from weak acids with K .ltoreq. 10-4.5 are considered proton acceptors. A non-linear least squares procedure is suggested to estimate the total alkalinity (AT) and total inorganic C (CT) of a seawater sample from potentiometric titration data. The approach offers a significant conceptual improvement over the currently used refined Gran functions. An estimate of the statistical uncertainty of the estimated values of AT and CT is available. As it is unnecessary to titrate beyond the alkalinity equivalence point, it may also be possible to speed up the titrations.