spectrometry mass spectrometry Mass spectroscopy is an obsolete synonym for mass spectrometry that should not be used to avoid confusion with spectroscopies in which the measured quantity is the absorption or emission of electromagnetic radiation. [IUPAC] mass spectroscopy Mass spectrometry is a spectrometry that studies matter through the formation of gas-phase ions that are characterized using mass spectrometers by their mass, charge, structure, and/or physico-chemical properties. [IUPAC] mass spectrometry MS Murray, K., Boyd, R., Eberlin, M., et al. (2013). Definitions of terms relating to mass spectrometry (IUPAC Recommendations 2013). Pure and Applied Chemistry, 85(7), pp. 1515-1609. The term is a misnomer because it is m/z rather than mass that is the independent variable in a mass spectrum. [IUPAC] mass analysis