Statistics on Parent-Daughter vs. Precursor-Product

January 21, 2005

Here are some statistics (from 2005) on the Parent vs. Precursor and Daughter vs. Product debate.

A little more than a dozen years ago, it was suggested that the terms Parent Ion and Daughter Ion be replaced with Precursor Ion and Product Ion, respectively (see Glish, J. Am Soc. Mass Spectrom, 2, 349, 1991). The rationale is to avoid gender-specific terms to describe inanimate objects.

A check of the literature suggests that a shift in usage has in fact occurred. In the figure below, the occurrence of Daughter Ion is plotted as a function of year. The number of occurrences has dropped by about one-half since the early 90s. Quantifying the occurrences of Product Ion is difficult since the phrase yields results that are not related to mass spectrometry.

The plot below show the occurrences of precursor ion and parent ion. From this plot, it appears that the former term is now being used more frequently in place of the latter.

A plot of the ratio of occurrences seems to drive home this point.

A remaining issue is the nomenclature for n^th generation product ions. Glish suggests x generation product ions where x=n-1 for a MSⁿ experiment.