Talk:Mass/charge Ratio

From Mass Spec Terms
Revision as of 08:32, 15 January 2005 by Ionworker (talk | contribs)

Jean-Fran??????????????ois GAL?????????????? 02-28-2004 10:07 AM ET (US)

"Mass/charge ratio Add your comment on this item (m/z) ratio." Sorry to insist ... Sparkman would say "mass-to-charge ratio".


m/z is wrong

let's get rid of the m/z. It is conceptually wrong. I made a new proposal.


I moved the Suggested Definition from the front page and used the new template:

{{Sugdef|m/z|The mass/charge ratio is a physical property that is measured by mass spectrometers.

The symbol for the physical quantity mass/charge is m/q. The former m/z is based on a missconception and should no longer be used.

The SI unit of the physical quantity m/q is kilogram/coulomb (kg/C). In mass spectrometry it is more common to use the Atomic Mass Unit u and the atomic unit for charge e which is equal to the elementary charge.

This means the unit for mass/charge is:

[m/q] = u/e

For simplicity, u is better called Dalton (Da) and e is called Millikan (Mi).

u/e is sometimes called Thomson (Th).

Therefore

[m/q] = u/e = Da/Mi = Th

Hence, a mass spectrum x-axis should be labeled as either of the below:

  • m/q (u/e)
  • m/q (Da/Mi)
  • m/q (Th)

(Note that this isn't my def, just my edit to put it on the Discussion page - KKM)

-- K. Murray 15:03, 13 Jan 2005 (CST)