COLLISIONALLY INDUCED DISSOCIATIVE IONISATION OF NEUTRAL SPECIES.

When ions fragment in the second field-free region of a ZAB 2F mass spectrometer the resulting ion beam will consist of unreacted ions (typically ca. 99%), daughter ions (0. 5%), and daughter neutrals (0. 5%), each having, generally, different kinetic energies. A deflector electrode, situated in front of the collision cell has been installed in the Ottawa ZAB 2F. Using this electrode to deflect the ion beam away from the cell, it was observed that several polyatomic negative ions (e. g. nitrobenzene** minus ) undergo a common reaction in the microsecond timeframe, being the loss of an electron, resulting in a beam of fast (8Kv) molecules. This deflector electrode technique is valuable for elucidating reaction mechanisms, and provides a relatively inexpensive way to study neutral-neutral collisions.