ABSTRACT The routine methods for stable oxygen and hydrogen isotope analysis of water involve water–CO2 gas equilibration and water reduction on hot metal (e.g. Zn, Cr, U) and subsequent mass spectrometric analysis of the evolved gases of CO2 and H2 for 18O/16O and 2H/1H ratios, respectively. Precise determination of the isotopic composition of water in brines with application of these standard methods is still problematic and technically often impossible due to detrimental influence of dissolved salts. The new method of brine desalination presented in this study overcomes the problem of the isotope salt effects encountered during the application of the routine techniques for the determination of the isotopic composition of high saline waters. The procedure combines two technical steps: (i) the chemical precipitation of Mg and Ca ions as insoluble non-hydroscopic fluorides, and (ii) the vacuum distillation of water from solution–precipitate mixture. The application of simple vacuum distillation allows full extraction of water and dehydration of remaining salts in a temperature range from 300 to 350 °C without hydrogen and oxygen isotope fractionation. The precision and accuracy of δ18O and δ2H determination of saline waters and brines with prior application of AgF desalination procedure is comparable with that usually obtained for fresh waters.

中文翻译：

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用于常规测定盐水和盐水中氧和氢同位素组成的 AgF 脱盐程序

摘要 水的稳定氧和氢同位素分析的常规方法包括水-CO2 气体平衡和铁水（例如 Zn、Cr、U）上的水还原以及随后对 18O/16O 的 CO2 和 H2 逸出气体的质谱分析和 2H/1H 比率，分别。由于溶解盐的有害影响，使用这些标准方法精确测定盐水中水的同位素组成仍然存在问题，并且在技术上通常是不可能的。本研究中提出的盐水淡化新方法克服了在应用常规技术测定高盐水同位素组成时遇到的同位素盐效应问题。该程序结合了两个技术步骤：(i) Mg 和 Ca 离子作为不溶性非吸湿性氟化物的化学沉淀，以及 (ii) 从溶液-沉淀混合物中真空蒸馏水。简单真空蒸馏的应用允许在 300 至 350 °C 的温度范围内完全提取水和脱水剩余的盐，而无需进行氢和氧同位素分馏。预先应用 AgF 脱盐程序对咸水和盐水进行 δ18O 和 δ2H 测定的精确度和准确度与通常在淡水中获得的精度和准确度相当。简单真空蒸馏的应用允许在 300 至 350 °C 的温度范围内完全提取水和脱水剩余的盐，而无需进行氢和氧同位素分馏。预先应用 AgF 脱盐程序对咸水和盐水进行 δ18O 和 δ2H 测定的精确度和准确度与通常在淡水中获得的精度和准确度相当。简单真空蒸馏的应用允许在 300 至 350 °C 的温度范围内完全提取水和脱水剩余的盐，而无需进行氢和氧同位素分馏。预先应用 AgF 脱盐程序对咸水和盐水进行 δ18O 和 δ2H 测定的精确度和准确度与通常在淡水中获得的精度和准确度相当。