抄録
Mass spectrometers separate ions according to each mass/charge value, which is not a dimensionless quantity. However, the m/z value indicated in the abscissa of mass spectra is defined as a dimensionless quantity and not a numerical value the same as the mass/charge value in kilograms/coulombs (kg/C) or in unified atomic mass units/coulombs (u/C). The numerical value of m/z converted from the mass/charge value depends on the unified atomic mass unit and the physical constant “elementary charge,” e that is also the atomic unit of charge. This conversion confuses many mass spectrometrists with regard to the abscissa labeling of mass spectra, e.g. the symbol “m/z” is considered as an abbreviation of the term “mass-to-charge ratio.”