Low‐energy ion/molecule products from collisions with ammonia

Multiple clustering of ammonia molecules to triply protonated bovine insulin B chain has been observed in a novel collision cell incorporated as part of a triple quadrupole mass spectrometer. The nature of the phenomenon was examined as a function of both the collision energy and the collision gas thickness in the cell. Increased clustering was observed with higher collision‐gas thickness and lower collision energy. Initial experiments indicate that the number of ammonia molecules clustering to the precursor ion may be dependent on the number of available acidic sites.