Instead of being ionized by a strong field which might fragment it (as in conventional mass spectroscopy), in chemical ionization mass spectroscopy, the sample is instead combined with an unstable electron-poor species which has been created by electron bombardment. The electron-poor species stabilizes itself by donating a hydrogen ion to the species under study, which is then shot through the spectrometer. An example of the technique follow.


(here, is the strongest acid).


A spike is then observed at CH₃CH₂OH