Collision-Induced Dissociation Study of the Adduct Ions Produced in NO3 (-)-Free Area of Atmospheric Pressure Negative Corona Discharges under Ambient Air Conditions.

Collision-induced dissociation (CID) experiments of adducts M+R with negative atmospheric ions R(-) (O2 (-), HCO3 (-) and COO(-)(COOH)) produced in NO3 (-)-free discharge area in atmospheric pressure corona discharge ionization (APCDI) method were performed using aliphatic and aromatic compounds M. The M+R adducts for individual R(-) fragmented to form deprotonated analytes M-H as well as the specific product ions which also occurred in the CID of M-H, independent of analytes with several different functional groups. The results obtained suggested that the specific product ions formed in the CID of M+R, as well as CID of M-H, are generated due to further fragmentation of the product ions M-H. It was concluded, therefore, that CID of M+R formed in NO3 (-)-free discharge area can indirectly lead to the formation of the product ions originating from M-H.