| Definitions of terms relating to mass spectrometry
(IUPAC Recommendations 2013)
has been published in Pure and Applied Chemistry
Mass Spectrometry Terms and Definitions Project
The goal of this site is to support the IUPAC project Standard definitions of terms relating to mass spectrometry that has resulted in the publication of Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013).
The wiki was open for comment between 2004 and 2006, was maintained as a reference from 2006 to 2013, and now contains links to numerous mass spectrometry terminology definitions from the IUPAC Gold Book, Orange Book, 2013 Recommendations, and other sources.
There are currently 1,799 entries in Mass Spectrometry Terms as of Monday January 21, 2019.
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Frequently asked questions
- Where can I get a PDF copy of the mass spectrometry terms document?
- The document can be found here: http://pac.iupac.org/publications/pac/85/7/1515/
- Can I republish the document contents?
- Contents of the document can be reproduced as long as IUPAC is acknowledged and the source is referenced and linked: "Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgment, with full reference to the source, along with use of the copyright symbol ©, the name IUPAC, and the year of publication, are prominently visible. Publication of a translation into another language is subject to the additional condition of prior approval from the relevant IUPAC National Adhering Organization."
- What was the IUPAC project that supported this work?
- It was Project 2003-056-2-500 "Standard definitions of terms relating to mass spectrometry". The planned duration was 2003–2006; the project was completed in the summer of 2013.
- Before this, what was the most recent set of recommendations for mass spectrometry terms?
- The last IUPAC recommendations were published in 1991.
- These definitions are locked in until 2035 then?
- No. The complete list of mass spectrometry terms should be updated every 5 to 10 years through community discussion and peer review as it had been prior to 1991. Individual terms, particularly contentious ones (e.g. resolution/resolving power, slashes and hyphens, CAD/CID), should be discussed and consensus definitions should be published in the peer-reviewed literature in the interim.
- Were the definitions presented for public comment?
- The terms were presented for public comment at the International Mass Spectrometry Conference, Edinburgh, September 2003; American Society for Mass Spectrometry Conference, Nashville, May 2004; British Mass Spectrometry Society Meeting, September 2005; American Chemical Society Conference, San Diego, March 2005; American Society for Mass Spectrometry Conference, San Antonio, June 2005; World Chemical Congress, Beijing, China, August, 2005; British Mass Spectrometry Society Meeting, September 2005; American Society for Mass Spectrometry Conference, Seattle, May 2006; and the International Mass Spectrometry Conference, Prague, August 2006. This website has been up since December 2003 and an e-mail listserver, MSTerms-L, was up from 2004–2006.
- Were the definitions peer reviewed?
- The manuscript was reviewed in nine drafts and received sixty individual reviews between initial submission in April of 2006 and acceptance in March of 2013.
- I found a definition of a term and I think that it is incorrect; what do I do?
- If you are convinced that a particular term is not correct, write a letter to the editor of a mass spectrometry journal or submit a short article with your new or modified definition(s) and rationale. Suitable references will strengthen your argument. Examples of short articles or letters to the editor on terminology can be found here: , , , , ,  Additionally, IUPAC supports projects aimed at definitions of specific terms, for example the definition of the hydrogen bond. See the IUPAC "Project Submission and Approval Process" page.
- You didn't include my favorite term; what do I do?
- See above. Write a letter to the editor with your new term and definition.
- How do I label the x-axis of a mass spectrum? And what are the units?
- Use m/z and it is dimensionless and it is an abbreviation, not a symbol. Do not use m/z(Da), m/z(u), m/e, and especially not m/z(amu). The thomson unit is not recommended.
- Is mass resolution Δm or m/Δm?
- The recommendations document retains the Gold Book definition m/Δm for resolution. There is considerable division regarding m/Δm vs. Δm and resolution vs. resolving power but the project task group found insufficient support for an alternative to the current Gold Book definition. Individuals pushing for a "Δm is resolution and m/Δm is resolving power" paradigm (or any alternative set of definitions) must work to achieve consensus on their definition, for example through an IUPAC project specifically for that term.
- When to use slashes and hyphens for combined methods? Is it GC/MS or GC-MS, LC/MS or LC-MS, etc?
- The current recommendation is to use either.
- Is it collision-induced dissociation (CID) and collisionally activated dissociation (CAD)?
- The current recommendation is to use either.
- Is TIC the recommended abbreviation for total ion current or total ion chromatogram?
- Use TIC for total ion current - use total ion current chromatogram (TICC) for the latter.