Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States.
Thermo Fisher Scientific, Somerset New Jersey 08873, United States.
J Am Soc Mass Spectrom. 2022 Jan 5;33(1):5-10. doi: 10.1021/jasms.1c00110. Epub 2021 Dec 6.
The current IUPAC-recommended definition of the term "monoisotopic mass" of a chemical species is based on the most abundant isotopes of the constituent elements. It has even been proposed to constrain the definition to be based only on the atomic masses of the most abundant stable isotopes. Such an approach is flawed because in this way several elements and their compounds, in addition to isotopically enriched species, would not merit to be assigned a monoisotopic mass. Furthermore, for large molecules, such as proteins, the monoisotopic mass as currently defined loses its significance. Therefore, we propose to eliminate using the current definition altogether. Instead, the term isotopologue mass should be applied uniformly to every species denoted by a specific chemical formula.
当前，化学物质“单一同位素质量”的 IUPAC 推荐定义基于组成元素的最丰富同位素。甚至有人提议将定义限制为仅基于最丰富稳定同位素的原子质量。这种方法是有缺陷的，因为这样一来，除了同位素富集物质外，还有一些元素及其化合物就不值得赋予单一同位素质量。此外，对于蛋白质等大分子，目前定义的单一同位素质量就失去了其意义。因此，我们建议完全摒弃当前的定义。相反，应该统一将“同位素标记物质量”这一术语应用于用特定化学式表示的每个物质。
