Fingerprinting stereoisomers by survivor‐ion mass spectrometry

Survivor‐ion mass spectrometry is used to distinguish stereoisomeric cis‐ and trans‐4‐methylcyclohexanol. The method involves producing ions by electron impact ionization and submitting them without mass selection to collisional neutralization and reionization, followed by selective monitoring of non‐dissociating ions. The differences in the electron impact mass spectra of the stereoisomers, due to the different fragment ion elemental compositions and structures, are highlighted by collisional neutralization with Xe, NO and CH3SSCH3, followed by reionization with oxygen. The differences in the survivor‐ion spectra are due to different neutralization efficiencies of the isobaric and isomeric ions produced by electron impact ionization, different stabilities of the intermediate neutral species, different reionization efficiencies and reionized ion stabilities. Neutralization‐reionization spectra of the C7H12+., C6H9+, C3H6O+. and C3H5O+ ions from stereoisomeric 4‐methylcyclohexanols are also reported.