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 mass spectrometry 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.
- What about resolving power?
- See resolving power and the comments above on mass resolution.
- 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 and that they are synonyms.
- Should I use the term daughter ion?
- Use product ion instead (also precursor ion not parent ion).
- Is ion-molecule reaction correct?
- No, use the slash: ion/molecule reaction.
- 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.
- Is MRM recommended?
- Yes, this was changed from an earlier recommendation. See multiple reaction monitoring, selected reaction monitoring, and consecutive reaction monitoring.
- Are new terms being added?
- Yes. Draft definitions are here. These are terms that were considered for the 2013 document or have been added after 2013. Terms that have been considered, but have no definition are here. For questions, comments, or suggestions for this site contact Kermit Murray.
Other mass spectrometry term compilations
Mass Spectrometry Web Glossaries
ASMS 'What is Mass Spectrometry?'
Base Peak Glossary
LBL Glossary of Nuclear Terms
Little Encyclopedia of MS
MDS Sciex "About Mass Spectrometry"
Shimadzu Mass Spectrometry Glossary
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