Analysis of natural products by tandem mass spectrometry employing reactive collisions with ethyl vinyl ether

Representative natural products from the diterpene dilactone, psorospermin and quabalactone classes were protonated, mass‐selected and reacted with ethyl vinyl ether in a triple‐quadrupole mass spectrometer. Minor differences in the structures of the compounds led to different reactivities toward the reagent, as indicated by the relative abundances of products such as the ethylated and vinylated compounds. Additional information is obtained from the dissociation products formed upon non‐reactive, inelastic collisions with the neutral reagent. The daughter spectra have excellent signal: noise ratios and good reproducibility. The results demonstrate that the use of reactive collisions may supplement collision‐activated dissociation in chemical analysis of large organic molecules by tandem mass spectrometry.