Talk:Resolving power (in mass spectrometry)

Kermit Murray?????????????? 01-30-2004 04:17 PM ET (US)

ASMS Terms and Definitions Poster has "mass resolving power - m/Dmx, where Dmx is the mass resolution "

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Glen Gregory??????????????

Glen Gregory?????????????? 02-28-2004 01:33 AM ET (US)

It should be noted that since Resolving Power is dimensionless, a specified mass/charge value should always be referenced for a given Resolving Power, i.e.- 5,000 Resolving Power for m/z 500. This allows for extrapolation across a broad mass range, such as the over all range of the MS instrument.

Alternatively, to simplify (and unify) resolution designation for non magnetic-sector instruments (those which exhibit constant peak width?????????????????????????s, such as ion trap's, ToF's, QToF's, and triple quad's), a common terminology used is "FWHM" (full width at half mass). This is the width of a mass peak (in amu, profile mode), half way up the height of the peak. This leads to the definition of a Gaussian peak with a 1 amu width at 10% base line, or "unit" resolution, as having 0.7 amu "FWHM" resolution. 0.7 FWHM now becomes the "standard" reference. With this definition, (again on constant peak width instruments only, such as the ones listed above), the lower the FWHM value, the better the resolution, regardless of m/z.