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Welcome to the Mass Spectrometry Terms and Definitions Project Page

This goal of this site is to provide information about and discussion of the IUPAC sponsored project to update the Standard Terms and Definitions for Mass Spectrometry. The site is built around a ' Wiki,' an on-line user editable glossary of mass spectrometry terms and definitions (for an example of a general WIki, see the Wikipedia).

User input in this project is invited and encouraged and for that reason, most of this site is open and editable. If you would like to edit an entry page on this site, just click on the edit tab and make changes in the edit box that appears. If you would like to make a comment, click on the ??????????????????????discussion????????????????????????? tab. Don?????????????????????????t worry about mistakes; all edits can be viewed and restored.

There are currently 2,240 entries in Mass Spec Terms as of Wednesday September 10, 2025.

Links

All Terms

Data, Detection, Ionization, Ions, m/z Separation, Sequential m/z Separation, Reactions

Proposed New Terms and Definitions

The working list of MS terms and definitions

IUPAC Orange Book Chapter 12

The current list of mass spectrometry terms

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Hot Topics

How should Resolution and Resolving Power be defined?

Should the Thomson be used instead of m/z?

Should be m/z be replaced by m/q?

How should Slashes and Hyphens be used in combined techniques?

Should Parent Ion/Daughter Ion be replaced with Precursor Ion/Product Ion? How about n^th generation products?