Mass (mass spectrometry): Difference between revisions

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Mass is a property of physical objects that reveals itself in two ways:
{{wplink}}
# as a resistance to change of velocity (inertia)
# as a force when exposed to a gravitational field


The symbol for the physical quantity mass is ''m''.
== See also ==
*[[Accurate Mass]]
*[[Average Mass]]
*[[Atomic Mass Unit]]
*[[Dalton]]
*[[Exact Mass]]
*[[Mass/charge Ratio]]
*[[Mass Number]]
*[[Mass Range]]
*[[Mass Spectrum]]
*[[Monoisotopic Mass]]
*[[Nominal Mass]]
*[[Thomson]]


The SI unit for mass is '''kg'''. In mass spectrometry it is more common to use the [[Atomic Mass Unit|unified atomic mass unit]] '''u''', which is better called [[Dalton]] '''Da'''.
{{defect}}


: ''m'' = n '''Da'''
{{nm}}


In spite of their name, [[Mass Spectrometer | mass spectrometers]] do not measure the mass of ions, but the [[Mass/charge Ratio| mass/charge]] ([[M/Q|m/q]]) of ions.
== External links ==
*[[Wikipedia: Mass]]


The mass of a particle (atom or molecule) is determined by the following components:
[[Category:Mass]]
# number of [[Wikipedia:nucleon|nucleons]] (protons and neutrons)
# number of electrons
# mass defect ([[Wikipedia:binding energy|binding energy]] of nucleons)
 
Because (1) protons and neutrons have simillar masses, and (2) the nucleons dominate the total mass, the total mass of particles is dominated by the number of nucleons. This has the effect that all particle masses are close integer numbers when measured in Dalton. Therefore another quantity has been useful in mass spectrometry, the quantity ''[[nominal mass]]''.
However, the term nominal mass is somewhat confusing since it is not clear if it just means a rounded mass or if it means the number of nucleons in a molecule.
 
: [[nucleon number]] ''N'' = n := number of nucleons in molecule
: [[nominal mass]] ''M'' = n '''Da''' := round(m)
 
 
 
 
 
== External Links ==
 
[[Wikipedia: Mass]]

Latest revision as of 16:30, 31 August 2017

WIKIPEDIA ARTICLE
This term has a corresponding Wikipedia article: Mass (mass spectrometry)
 

See also

Mass defect

Mass defect in mass spectrometry and nuclear physics

Mass defect (mass spectrometry)
The difference between the exact mass and the nearest integer mass
Mass defect (physics)
The difference between the mass of a composite particle and the sum of the masses of its parts

Links

Land, A. Neutrons in the Nucleus. I. Phys. Rev. 43, 620-623 (1933).
http://dx.doi.org/10.1103/PhysRev.43.620
Carlson (1960); High Resolution Mass Spectrometry. Interpretation of Spectra of Petroleum Fractions
http://dx.doi.org/10.1021/ac60167a032
Kendrick (1963); A Mass Scale Based on CH2= 14.0000 for High Resolution Mass Spectrometry of Organic Compounds.
http://dx.doi.org/10.1021/ac60206a048
Hughey (2001); Kendrick Mass Defect Spectrum:? A Compact Visual Analysis for Ultrahigh-Resolution Broadband Mass Spectra
http://dx.doi.org/10.1021/ac010560w
Zhang (2003); A software filter to remove interference ions from drug metabolites in accurate mass liquid chromatography/mass spectrometric analyses
http://dx.doi.org/10.1002/jms.521
Hall, M.P., Ashrafi, S., Obegi, I., Petesch, R., Peterson, J.N., Schneider, L.V. Mass defect tags for biomolecular mass spectrometry. J. Mass Spectrom. 38, 809-816 (2003).
http://dx.doi.org/10.1002/jms.493
Zhang (2009); Mass defect filter technique and its applications to drug metabolite identification by high-resolution mass spectrometry
http://dx.doi.org/10.1002/jms.1610
Sleno (2012); The use of mass defect in modern mass spectrometry
http://dx.doi.org/10.1002/jms.2953
Pourshahian (2017); Mass Defect from Nuclear Physics to Mass Spectral Analysis
http://dx.doi.org/10.1007/s13361-017-1741-9

Nominal mass

Related definitions

Other definitions

Mallet and Down ISBN 0470027614
"The mass of a molecule or ion calculated using the integral masses of the most abundant isotopes of each element present"
Sparkman ISBN 0966081390
"The integer mass of the most abundant naturally occurring stable isotope of an element ... the nominal mass of an element is equal to the mass number of the most abundant stable isotope of an element"
de Hoffmann ISBN 0470033118
"The nominal mass is calculated using the mass of the predominant isotope of each element rounded to the nearest integer value that corresponds to the mass number ..."
Watson and Sparkman ISBN 0470516348
"The nominal mass of an element is the integer mass of its most abundant stable isotope ... the nominal mass of a molecule, radical, or ion is the sum of the nominal masses of all the atoms of its constituent elements." (common organic elements this is the lowest but not always)
Gross ISBN 3642423469
"the nominal mass of an element is defined as the integer mass of its most abundant naturally occurring stable isotope ... the nominal mass of an ion is the sum of the nominal masses of its constituent elements."

References

External links