COLLISION-INDUCED DISSOCIATION (CID) PROCESSES IN SOME CARBAMATE AND PHENYLUREA PESTICIDES STUDIED BY ION-TRAP MS MS/

A series of carbamate and phenylurea pesticides was studied by ion-tra p MS/MS collision-induced dissociation (CID) in the resonant excitatio n mode. CID mass spectra contained highly abundant daughter ions forme d by simple cleavage as well as by rearrangement processes. The format ion of rearrangement daughter ions vs. cleavage daughter ions was foun d to be dependent on the CID voltage and CID time in some of the inves tigated compounds. The relative intensity of the ions formed by cleava ge, i.e. via high-energy pathways, vs. ions formed through rearrangeme nt processes, i.e. via low-energy pathways, increased with increasing collision energy. A similar effect was obtained by increasing the CID time, thus enabling the ions to gain more energy and consequently form more cleavage ions than rearrangement ions. (C) 1997 Elsevier Science B.V.