Laboratoire de Géochimie des Eaux, Universite Paris Diderot, IPGP, UMR CNRS 7154, Case Postale 7052, 75025 Paris, Cedex 13, France.
Environ Sci Technol. 2010 Sep 1;44(17):6782-8. doi: 10.1021/es1012142.
Potentiometric titration is a common method to characterize dissolved organic matter (DOM) reactivity. Because of the sensitivity of pH electrodes, it is necessary to work with very high DOM (>1 g/L) concentrations that are unrealistic compared to those found in natural waters (0.1 to 100 mg/L). To obtain proton binding data for concentrations closer to environmental values, spectroscopic titration methodology is a viable alternative to traditional potentiometric titrations. Spectrophotometric titrations and UV-visible spectra of a diluted solution of purified Aldrich humic acid (5 mgDOC/L) are used to estimate changes in proton binding moieties as function of pH and ionic strength after calculation of differential absorbance spectra variations. After electrostatic correction of spectrophotometric data, there is a linear operational correlation between spectrophotometric and potentiometric data which can be used as a transfer function between the two properties. Spectrophotometric titrations are then used to determine the changes of humic acid protonation after adsorption onto alpha-alumina.
电位滴定法是一种常见的方法来描述溶解有机质（DOM）的反应性。由于 pH 电极的灵敏度，需要处理非常高的 DOM（>1 g/L）浓度，这与在天然水中发现的浓度（0.1 到 100 mg/L）相比是不现实的。为了获得更接近环境值的浓度的质子结合数据，光谱滴定方法是传统电位滴定的可行替代方法。分光光度滴定法和经稀释的纯化 Aldrich 腐殖酸（5 mgDOC/L）溶液的紫外可见光谱用于在计算差示吸收光谱变化后估计质子结合部分随 pH 和离子强度的变化。对分光光度数据进行静电校正后，分光光度数据和电位滴定数据之间存在线性操作相关性，可作为两种特性之间的传递函数。然后使用分光光度滴定法来确定腐殖酸在α-氧化铝上吸附后质子化的变化。
