fixed precursor ion scan

in mass spectrometry
A scan which determines, in a single experiment, all the daughter ion mass-to-charge ratios that are produced by the reaction of a selected parent ion mass-to-charge ratio.
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 1551