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| I think that we may be stuck with the unitless ''m/z.'' But you are correct, this is a confusing point.
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| Sparkman recommends against the [[Thomson]] unit.
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| : - Kermit Murray
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| :Unfortunately I don't have the book of Sparkman available. What is his line of argument? I used to be in favor of the "unitles" m/z. Now I think it is a folly. Maybe we can declare m/z as dimension- and unitles. We could also declare current, voltage, length, time, speed, weight, force and any other property as dimensionles. We could also remove all the labels from every bottle, we could purge the names of all streets, cities and countries. However, the confusion only gets bigger. The concept of dimensions and units is an important scientific and cultural achievements of humanity. It helps naming and measuring things, and enables communication about it. And we, the mass spec community, make fools of ourselves if we ignore this achievement. Or did I miss something?
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| : -Ionwerker
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| Here's Sparkman (p 27 of [http://www.lcms.com/msdr_book.ht Mass Spec Desk Reference])
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| <blockquote>????????????????????????Although this term is the official usage as prescribed in the ''Current IUPAC Recommendations'' and the ASMS guidelines, unfortunately, ''' ''m/z'' ''' is a mass spectrometry neologism. In SI units, the lowercase letter '''m''' is the symbol for the meter. The symbol for atomic mass is the lower case '''u'''. Therefore, the correct abbreviation for a mass spectral ion or a peak in a mass spectrum should be u/z ?????????????????????? This term has never been used. The single term ''m/z'' is a symbol, not an abbreviation.?????????????????????? </blockquote>
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| He goes on to say that ????????????????????????''m/z'' is a symbol, not a mathematical formula?????????????????????? even though it looks like a mass divided by a charge number (and can often be treated in this way. The current convention is to use dimensionless "''m/z'' units" and hope the confusion stays at a minimum. The thomson unit is an attempt to reduce this confusion, but it adds some new confusions due to similar terms in physics.
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| : - Kermit Murray
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