Comparative study of ion kinetic energy,chemical ionisation and field desorption spectra

A comparison of the fragmentation processes operating in the first field free region was made with the fragmentation in the ion source under electron ionisation, chemical ionisation and field desorption conditions for some selected compounds which undergo retro-DielsI-Alder fragmentation in the ion source under electron ionisationconditions. The fragmentation processes which com-ete with retro-Diels-Alder fragmentation under chemical ionisation and field desorption conditions are discussed. The complementary nature of these techniques are illustrated.