00992 IUPAC Gold Book - charge-inversion mass spectrum 10.1351/goldbook.C00992 C00992 current 1 Charge inversion processes of the types: or or respectively, occuring in a collision cell (containing a gas, X) located in a field-free region preceding a magnetic and electric sector combination placed in either order, may be detected as follows. If the instrument slits are wide, and if the connections to the two sectors, appropriate to transmission of either positive or negative main-beam ions, are simply reversed, the negative or positive product ions of the two processes, respectively, will be transmitted. If the magnetic field is scanned, a spectrum of such product ions will be obtained, and this spectrum is called a charge-inversion mass spectrum. These spectra are sometimes referred to as −E and +E spectra, respectively. The terms '2E, E/2, −E or +E mass spectrum' should not be used without prior explanation of the meaning 2E, E, +E or −E. inversion https://goldbook.iupac.org//terms/view/I03146 mass spectrum https://goldbook.iupac.org//terms/view/M03749 transmission https://goldbook.iupac.org//terms/view/T06477 PAC, 1991, 63, 1541. 'Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)' on page 1551 (https://doi.org/10.1351/pac199163101541) https://goldbook.iupac.org/terms/view/C00992/html https://goldbook.iupac.org/terms/view/C00992/json https://goldbook.iupac.org/terms/view/C00992/plain Citation: 'charge-inversion mass spectrum' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.C00992 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-07-25T08:09:03+00:00