Abstract: A combination of collision-induced dissociation (CID) and ion-molecule (I-M) reaction was used to study the re-equilibrium procedure which occurred in an ion trap mass spectrometer when collision-induced dissociation (CID) as the constant disturbance was imparted to an isolated metal complex. The re-equilibrium in the gas phase was found to proceed through ligand loss, gain or exchange reaction with the participation of solvent molecules: methanol and water. Semi-quantitative CID measurements depending on the activation time were carried out. The comparison among the kinetic behaviors of the cycled metal complexes reveals that the chemical re-equilibrium occurred in the gas-phase system is depended on the thermodynamic stability of metal complex. The feature of CID can be used to study the stability of metal complex in ion trap mass spectrometry by controlling the activation time.