Raman spectroscopic study for the determination of Cl − concentration (molarity scale) in aqueous solutions: Application to fluid inclusions
Raman spectroscopic study for the determination of Cl − concentration (molarity scale) in aqueous solutions: Application to fluid inclusions
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DOI：
10.1016/j.chemgeo.2010.02.004
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发表时间：
2010-04
期刊：
影响因子：
3.9
通讯作者：
Qiang Sun;Lei Zhao;Nuo Li;Jin Liu
中科院分区：
文献类型：
--
作者：
Qiang Sun;Lei Zhao;Nuo Li;Jin Liu
从最近对碱和碱性氯化物水溶液结构的研究中可以推断，一价和二价阳离子的影响很小，水-氯化物相互作用是主要负责的解决方案。因此，Cl−摩尔浓度可以作为描述这些系统的重要参数。本文合成了NaCl-H_2 O、KCl-H_2 O、CaCl_2-H_2 O、MgCl_2-H_2 O和NaCl-KCl-CaCl_2-H_2 O体系，并记录了它们的拉曼光谱。从溶液的拉曼OH伸缩谱带可以区分出溶液的等吸光点。这说明各种结构物种之间存在着平衡，拉曼OH振动可以用来研究这些溶液的盐度。本研究将拉曼OH振动用两个高斯子带拟合，确定平衡常数，进而确定Cl−浓度（摩尔浓度标度）的校准方程。在讨论了基质矿物的双折射对拉曼OH伸缩带的影响后，将该方法应用于天然流体包裹体盐度的测量。
From recent studies on the structure of aqueous alkali and alkaline chloride solutions, it can be deduced that the effects of monovalent and divalent cations are small, and water–chloride interactions are primarily responsible for the solutions. Therefore, Cl−molarity can be treated as an important parameter in describing these systems. In this work, the NaCl–H2O, KCl–H2O, CaCl2–H2O, MgCl2–H2O and NaCl–KCl–CaCl2–H2O systems are synthesized, and their Raman spectra are recorded. From the Raman OH stretching bands of the solutions, the isosbestic points can be discriminated. This means that there exists the equilibrium between various structural species, the Raman OH vibration can be applied to study the salinity of these solutions. In this study, the Raman OH vibration is fitted with two Gaussian sub-bands, the equilibrium constant can be determined, then the calibration equation of Cl−concentration (molarity scale) can be determined. After the effects of the birefringence of the host mineral on the Raman OH stretching bands are discussed, the method is applied to measure the salinity of natural fluid inclusions.