2017/04/19 by Caiming Tang, Tang, Caiming, Xianzhi Peng +1 · 1 citation
Chemistry · Environmental Science · Physics and Astronomy · #Analytical chemistry methods development #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Isotope Analysis in Ecology #Radioactive element chemistry and processing #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.1704.05607
50 pages, 6 figures
openalex publication_date 2017/04/19 · arxiv created 2017/07/04 · arxiv updated 2017/07/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Revelation of the effects of isotope fractionation during fragmentation in electron ionization mass spectrometry (EI-MS) on compound-specific isotope analysis of chlorine and bromine (CSIA-Cl/Br) may be of crucial significance, yet a theoretical basis for elucidating the effects is absent. This study provides a solid theoretical deduction regarding the isotope fractionation taking place during fragmentation in EI-MS. Both intermolecular and intramolecular isotope fractionations present in dehalogenation processes, influencing the isotope ratios of detected ions. In general, intermolecular isotope fractionation positively affects the isotope ratios of precursor ions but inversely impacts those of the corresponding product ions. Molecular ions are normally affected by one type of intermolecular isotope fractionation only during the dehalogenation from parent ions to their product ions. While product ions can be impacted by two types of intermolecular isotope fractionations, namely, the inverse intermolecular isotope fractionation from parent ions to their product ions and the normal intermolecular isotope fractionation from the product ions to their further dehalogenated product ions. For a compound having position-distinct isotope ratios, if dehalogenation reacts on only one position, the intermolecular isotope fractionation taking palace in this reaction is normal for the detected precursor ion, but ineffective to the product ion isotope ratio in comparison with that of the total precursor ions. On the other hand, intramolecular isotope fractionation positively affects the isotope ratios of product ions only. The chlorine isotopologues of the observed precursor ions are deduced to never obey binomial distribution, regardless of what modes of the initial isotopologue distributions of the total precursor ions are.