Phosphoric acid digestion of carbonate generates CO₂ for stable oxygen and clumped isotope analysis using a gas source isotope ratio mass spectrometer. The initial step of digestion reaction is protonation of calcite while the product CO₂ equilibrates with the system allowing further exchange of isotopes to various extents depending on the nature of acid digestion methods. An external electric field is introduced in the break seal method to demonstrate the role of the protonation reaction and the post‐digestion isotopic exchanges in the final isotopic composition of product CO₂.

中文翻译：

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在存在外部直流电场的情况下，方解石酸的酸消化过程中，稳定氧和成簇的同位素分馏。

碳酸盐的磷酸消化可产生用于稳定氧的CO ₂以及使用气源同位素比率质谱仪进行的团聚同位素分析。消化反应的第一步是使方解石质子化，同时使产物CO ₂与系统平衡，从而根据酸消化方法的性质，在不同程度上进一步交换同位素。断裂密封方法中引入了外部电场，以证明质子化反应和消化后的同位素交换在产物CO ₂的最终同位素组成中的作用。