Mass-to-charge ratio

The mass-to-charge ratio is the physical quantity ^m ⁄ _q , the reciprocal of the specific charge . The SI unit is kg / C . In the past the unit Thomson (Th) was also used, 1 Th = 1 u / e .

In the mass is ^m / _z of IUPAC recommended as an abbreviation or symbol. Therein is "m" for the mass of the particle as a multiple of the atomic mass unit, u , and "z" for the amount of the charge number of the particle (which is always positive, even for ions having a negative charge). There is no connection to the Thomson unit because a mass-charge ratio expressed in Th can also be negative. The Thomson unit is “deprecated”, its use is explicitly discouraged.

The use of “ ^m ⁄ _z ” is restricted: The symbol “ ^m ⁄ _z ” denotes the horizontal axis of mass spectra with such abscissa values (without units). Calculating with ^m ⁄ _z in formulas is not recommended. The mass-to-charge ratio of a particle is, e.g. B. m / z 100 written, not m / z = 100th "M / z" is always written in italics.

literature

Kermit K. Murray et al .: Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013) . In: Pure and Applied Chemistry. Vol. 85, No. 7, 2013, pp. 1515–1609, doi: 10.1351 / PAC-REC-06-04-06 (free full text, entry 356).

Individual evidence

↑ ^a ^b M / z - Mass Spectrometry Terms. Accessed February 13, 2018 .
↑ Kermit K. Murray, Robert K. Boyd, Marcos N. Eberlin, G. John Langley, Liang Li: Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013) . In: Pure and Applied Chemistry . tape 85 , no. 7 , June 6, 2013, ISSN 0033-4545 , p. 1515–1609 , doi : 10.1351 / PAC-REC-06-04-06 ( iupac.org [accessed February 13, 2018]).
^ Thomson - Mass Spectrometry Terms. Accessed February 13, 2018 .
^ Dietrich A. Volmer: Terms and acronyms that should be avoided in mass spectrometry publications . In: Rapid Communications in Mass Spectrometry . tape 28 , no. 17 , September 15, 2014, ISSN 1097-0231 , p. 1853–1854 , doi : 10.1002 / rcm.6979 ( wiley.com [accessed February 13, 2018]).

[:0-1] M / z - Mass Spectrometry Terms. Accessed February 13, 2018 .

[2] Kermit K. Murray, Robert K. Boyd, Marcos N. Eberlin, G. John Langley, Liang Li: Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013) . In: Pure and Applied Chemistry . tape 85 , no. 7 , June 6, 2013, ISSN 0033-4545 , p. 1515–1609 , doi : 10.1351 / PAC-REC-06-04-06 ( iupac.org [accessed February 13, 2018]).

[3] Thomson - Mass Spectrometry Terms. Accessed February 13, 2018 .

[4] Dietrich A. Volmer: Terms and acronyms that should be avoided in mass spectrometry publications . In: Rapid Communications in Mass Spectrometry . tape 28 , no. 17 , September 15, 2014, ISSN 1097-0231 , p. 1853–1854 , doi : 10.1002 / rcm.6979 ( wiley.com [accessed February 13, 2018]).