Ion-attachment mass spectrometry

Ion-attachment mass spectrometry (IAMS) is a form of mass spectrometry that uses a "soft" form of ionization similar to chemical ionization in which a cation is attached to the analyte molecule in a reactive collision:

${\displaystyle {\ce {{M}+ {X+}+ A -> {MX+}+ A}}}$

Where M is the analyte molecule, X⁺ is the cation and A is a non-reacting collision partner.