Resolution (mass spectrometry)

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IUPAC RECOMMENDATIONS 2013

K. K. Murray, R. K. Boyd, M. N. Eberlin, G. J. Langley, L. Li and Y. Naito, Pure Appl. Chem., 2013, 85, 1515-1609, 10.1351/PAC-REC-06-04-06.

Resolution (mass spectrometry)
In a mass spectrum, the observed m/z value divided by the smallest difference Δ(m/z) for two ions that can be separated: (m/z)/Δ(m/z).
Note 1: The m/z value at which the measurement was made should be reported.
Note 2: The definition and method of measurement of Δ(m/z) should be reported. Commonly this is performed using peak width measured at a specified percentage of peak height.
Note 3: Alternatively Δ(m/z) is defined as the separation between two adjacent equal magnitude peaks such that the valley between them is a specified fraction of the peak height, for example as measured by peak matching.
Related Term(s): Resolving power
Reference(s):

IUPAC. Analytical Division. Compendium of Analytical Nomenclature (the “Orange Book”). Definitive Rules, 1979. Compiled by J. Inczédy, T. Lengyel, A. M. Ure. Blackwell Scientific Publications, Oxford (1997). On-line corrected version: http://www.iupac.org /publications/analytical compendium (2000).

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins.

G. L. Glish, D. J. Burinsky. J. Am. Soc. Mass Spectrom. 19, 161 (2008).

J. Laskin, J. H. Futrell. Mass Spectrom. Rev. 24, 135 (2005).

Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013); DOI: 10.1351/PAC-REC-06-04-06 © IUPAC 2013.


Index of Terms

 




Gold Book

GOLD BOOK DEFINITION

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).

Resolution (mass spectrometry)

resolution in mass spectroscopy [sic]

(energy): By analogy with the peak width definition for mass resolution, a peak showing the number of ions as a function of their translational energy should be used to give a value for the energy resolution.

(10 per cent valley definition): Let two peaks of equal height in a mass spectrum at masses m and m - Δm be separated by a valley which at its lowest point is just 10 per cent of the height of either peak. For similar peaks at a mass exceeding m, let the height of the valley at its lowest point be more (by any amount) than ten per cent of either peak height. Then the resolution (10 per cent valley definition) is m/Δm. It is usually a function of m. The ratio m/Δm should be given for a number of values of .

(peak width definition): For a single peak made up of singly charged ions at mass in a mass spectrum, the resolution may be expressed as m/Δm where Δm is the width of the peak at a height which is a specified fraction of the maximum peak height. It is recommended that one of three values 50%, 5% or 0.5% should always be used. For an isolated symmetrical peak recorded with a system which is linear in the range between 5% and 10% levels of the peak, the 5% peak width definition is technically equivalent to the 10% valley definition. A common standard is the definition of resolution based upon being Full Width of the peak at Half its Maximum height, sometimes abbreviated 'FWHM'. This acronym should preferably be defined the first time it is used.

Source: PAC, 1991, 63, 1541 (Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)) on page 1554

Orange Book, p. 203

IUPAC Gold Book
Index of Gold Book Terms


Orange Book

ORANGE BOOK DEFINITION

IUPAC. Analytical Division. Compendium of Analytical Nomenclature (the “Orange Book”). Definitive Rules, 1979.

Resolution (mass spectrometry)

Resolution: 10 Per Cent Valley Definition

Let two peaks of equal height in a mass spectrum at masses m and m - Δm be separated by a valley which at its lowest point is just 10% of the height of either peak. For similar peaks at a mass exceeding m , let the height of the valley at its lowest point be more (by any amount) than 10% of either peak. Then the resolution (10% valley definition) is m / Δm. The ratio m /Δm should be given for a number of values of m.

Resolution: Peak Width Definition

For a single peak made up of singly charged ions at mass m in a mass spectrum, the resolution may be expressed as m / Δm, where Δm is the width of the peak at a height which is a specified fraction of the maximum peak height. It is recommended that one of three values 50%, 5% or 0.5% should always be used. (Note that for an isolated symmetrical peak recorded with a system which is linear in the range between 5% and 10% levels of the peak, the 5% peak width definition is equivalent to the 10% valley definition. A common standard is the definition of resolution based upon Δm being Full Width of the peak at Half its Maximum (FWHM) height.

IUPAC Orange Book Chapter 12
Index of Orange Book Terms


Resolution and resolving power controversy

QUOTED TEXT FROM IUPAC RECOMMENDATIONS 2013
The IUPAC definition of resolution in mass spectrometry expresses this value as m/Δm, where m is the mass of the ion of interest and Δm is the peak width (peak width definition) or the spacing between two equal intensity peaks with a valley between them no more than 10 % of their height (10 % valley definition) [1]. Resolving power in mass spectrometry is defined as the ability of an instrument or measurement procedure to distinguish between two peaks at m/z values differing by a small amount and expressed as the peak width in mass units [2]. Mass resolving power is defined separately as m/Δm in a manner similar to that given above for mass resolution [3]. These definitions of mass resolving power and resolving power in mass spectrometry are contradictory, the former is expressed as a dimensionless ratio and the latter as a mass. The definitions for resolution in mass spectrometry and resolving power in mass spectrometry come from Todd’s 1991 recommendations [4], and the definition for mass resolving power comes from Beynon’s 1978 recommendations [5]. Beynon’s work contains no definition for mass resolution.

Alternative definitions for resolution and resolving power in mass spectrometry have been proposed [6][7]. It has been suggested that resolution be given by Δm and resolving power by m/Δm; however, these definitions are not widely used.

The majority of the mass spectrometry community uses resolution as defined by IUPAC. The term resolving power is not widely used as a synonym for resolution. In this document, the IUPAC definition of resolution in mass spectrometry remains in place. The definition of resolving power has been adapted from the current IUPAC definition of mass resolving power.

From Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013); DOI: 10.1351/PAC-REC-06-04-06 © IUPAC 2013.


Books defining resolution and/or resolving power

Books using “resolution is m/Δm”

Mass Spectrometry and its Applications to Organic Chemistry
J. H. Beynon, Elsevier, 1960
p. 51 "The terms 'resolution' and 'resolving power' have been used a great deal in the above discussion. It has been assumed that the doublet is 'resolved' when its constituent ion species are 'separated' and that the difficult of separation or 'resolving power' necessary to separate the adjacent mass peaks is given by M/ΔM."
Mass Spectrometry – Organic Chemical Applications
Klaus Biemann, McGraw-Hill, 1962
(p. 13) “the term ‘resolution’ is used in different ways … Throughout this book resolution will be considered as M/ΔM …”
Lasers and Mass Spectrometry
By David M. Lubman, Oxford University Press US, 1990, ISBN 0195059298
Interpretation of Mass Spectra
Fred W. McLafferty, Turecek, University Science Books, 1993, Language: English, ISBN 0935702253
Mass Spectrometry: Clinical and Biomedical Applications
By Dominic M. Desiderio, Springer, 1993, ISBN 0306442612
Practical Organic Mass Spectrometry: A Guide for Chemical and Biochemical Analysis
J. R. Chapman, Wiley_Default, 1995, ISBN 047195831X
Mass Spectrometry for Chemists and Biochemists
Robert Alexander Walker Johnstone, M. E. Rose, Cambridge University Press, 1996, ISBN 0521424976
Introduction to Mass Spectrometry
By J. Throck Watson, Lippincott-Raven, 1997, ISBN 0397516886
Ionization Methods in Organic Mass Spectrometry
By Alison E. Ashcroft, Royal Society of Chemistry (Great Britain), Royal Society of Chemistry, 1997, ISBN 0854045708
Accelerator Mass Spectrometry: Ultrasensitive Analysis for Global Science
Claudio Tuniz, John R. Bird, Gregory F. Herzog, David Fink, CRC Press, 1998, ISBN 0849345383
Mass Spectrometry in Biology & Medicine
By A. L. Burlingame, Steven A. Carr, Michael A. Baldwin, Humana Press, 1999, ISBN 0896037991
Mass Spectrometry and Genomic Analysis
J. Nicholas Housby, Springer, 2001, ISBN 0792371739
Mass Spectrometry Basics
Christopher G. Herbert, Robert Alexander Walker Johnstone, CRC Press, 2002, ISBN 0849313546
Liquid Chromatography Mass Spectrometry: An Introduction Robert E. Ardrey
Wiley, 2003, ISBN 0471498017
Mass Spectrometry: A Textbook
Jürgen H. Gross, Springer, 2004, ISBN 3540407391
Quadrupole Ion Trap Mass Spectrometry
By Raymond E. March, John F. Todd, Wiley-IEEE, 2005, ISBN 0471717975
The Expanding Role of Mass Spectrometry in Biotechnology
Gary Siuzdak, McC Pr, 2006, ISBN 0974245127
Quantitative Applications of Mass Spectrometry
Pietro Traldi, Franco Magno, Irma Lavagnini, Roberta Seraglia, Wiley, 2006, ISBN 0470025166
Assigning Structures to Ions in Mass Spectrometry
John L. Holmes, Christiane Aubry, Paul M. Mayer, CRC, 2006, ISBN 0849319501
Mass Spectrometry: Principles and Applications
Edmond de Hoffmann, Vincent Stroobant, Wiley-Interscience, 2007
ISBN 047003310X
Mass Spectrometry: Principles and Applications
Edmond de Hoffmann, Jean Charette, Vincent Stroobant, Wiley, 1996, ISBN 0471966975
p 287: "Resolution: the ratio of m/δm where m and m+δm are the mass numbers of the two ions that yield neighboring peaks with a valley depth of x% of the weakest peak's intensity."
Quantitative Proteomics by Mass Spectrometry (Methods in Molecular Biology)
Salvatore Sechi, Humana Press, 2007, ISBN 1588295710
Computational Methods for Mass Spectrometry Proteomics
Ingvar Eidhammer, Kristian Flikka, Lennart Martens, Svein-Ole Mikalsen, Wiley-Interscience, 2008, ISBN 0470512970

Books that use “resolution is Δm”

Mass Spectrometry Desk Reference
David Sparkman, Global View, 2006, ISBN 0966081390
"Incorrect: resolution – when defined in the same way as resolving power. Resolution is the inverse of resolving power and expressed as ΔM at M."
Introduction to Mass Spectrometry: Instrumentation, Applications, and Strategies for Data Interpretation
J. Throck Watson, O. David Sparkman, Wiley, 2007, Language: English, ISBN 0470516348
Fundamentals of Contemporary Mass Spectrometry
Chhabil Dass, 2007, ISBN 0471682292
p. 68: "[mass resolution] is the inverse of resolving power (RP), given as RP=m/Δm"
Proteomics in Practice: A Guide to Successful Experimental Design
Reiner Westermeier, Tom Naven, Hans-Rudolf Höpker, Wiley, 2008, ISBN 3527319417

Other IUPAC definitions of resolution

Gold Book

GOLD BOOK DEFINITION

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).

Resolution (mass spectrometry)

http://goldbook.iupac.org/R05319.html

resolution (in optical spectroscopy)

Wavenumber, wavelength or frequency difference of two still distinguishable lines in a spectrum.

Source: Green Book, 2nd ed., p. 31


IUPAC Gold Book
Index of Gold Book Terms


Gold Book

GOLD BOOK DEFINITION

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).

Resolution (mass spectrometry)
http://goldbook.iupac.org/P04465.html

peak resolution, Rs (in chromatography)

The separation of two peaks in terms of their average peak width at base (t R2 > t R1):

R s = t R2 ? t R1 w b1 + w b2 2 = 2 ( t R2 ? t R1 ) w b1 + w b2

In the case of two adjacent peaks it may be assumed that w b1 ? w b2, and thus, the width of the second peak may be substituted for the average value:

R s = t R2 ? t R1 w b2

Source: PAC, 1993, 65, 819 (Nomenclature for chromatography (IUPAC Recommendations 1993)) on page 847

Orange Book, p. 108

IUPAC Gold Book
Index of Gold Book Terms


Gold Book

GOLD BOOK DEFINITION

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).

Resolution (mass spectrometry)

resolution (in gas chromatography)

http://goldbook.iupac.org/R05317.html

A characteristic of the separation of two adjacent peaks. It may be expressed according to the equation:

RAB = 2(|dR(B)-dR(A)|)/(|wB+ wA|)

where RAB is the resolution, dR (A) and dR (B) are the retention distances (time or volume) of each eluted component A and B, and wA and wB are the respective widths of each peak at its base.

PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2211

IUPAC Gold Book
Index of Gold Book Terms


Gold Book

GOLD BOOK DEFINITION

IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”). Compiled by A. D. McNaught and A.Wilkinson. Blackwell Scientific Publications, Oxford (1997).

Resolution (mass spectrometry)
http://goldbook.iupac.org/E02113.html

energy resolution (in radiochemistry)

A measurement, at given energy, of the smallest difference between the energies of two particles or photons capable of being distinguished by a radiation spectrometer.

Source: PAC, 1994, 66, 2513 (Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)) on page 2519

IUPAC Gold Book
Index of Gold Book Terms