## fragmentation reaction

in mass spectrometry
https://doi.org/10.1351/goldbook.F02507
A @F02506@ reaction may be written: $\text{M}_{1}^{+}\rightarrow \text{M}_{2}^{+}+\text{M}_{3}$ The @D01547@ of a @M03872@ ion of mass-to-charge ratio $$\frac{m_{1}}{z_{1}}$$ into an ion of mass-to-charge ratio $$\frac{m_{2}}{z_{2}}$$ after electric @A00051@ of the @M03872@ ion and before magnetic deflection gives rise to a peak in the @M03749@ at an apparent mass, $$\frac{m_{2}^{2}\ z_{1}}{m_{1}\ z_{2}^{2}}$$. The symbol $$m^{*}$$ should be used to indicate the apparent mass of the product ions giving rise to this peak. Traditionally, the peak itself has been called a @M03872@ peak and this should preferably be expressed as @M03874@ peak. It is nevertheless recommended that the former term should be retained. The word @M03872@ should never be used as a noun. Its use as an adjective should be limited to such terms as @M03872@ ion, where it is used correctly, and to the special case of @M03872@ peak discussed above. It should never be used in such terms as @M03872@ reaction, @M03872@ @D01547@, @M03872@ studies, etc. It should be clear that the @M03872@ ion is the ion that undergoes @F02506@; it is not detected. When a reaction is written with an asterisk above the arrow as shown: $\text{M}_{1}^{+}\overset{\text{*}}{\rightarrow }\text{M}_{2}^{+}+\text{M}_{3}$ this means that the reaction has been confirmed by the observation of a @M03872@ peak. The textual description of such a process may be written as, for example, ($$m^{*}$$, $$43\rightarrow 28$$, calcd. 18.2, obsd. 18.3) meaning 'for the @F02506@ $$\frac{m}{z}\ 43\rightarrow \frac{m}{z}\ 28$$ a @M03872@ peak at $$\frac{m}{z}$$ 18.3 (calculated 18.2) has been observed'.
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 1557 [Terms] [Paper]