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Ion kinetic energy spectroscopy(IKES)provides new and useful information on the structure of ions formed by mass spectrometer. This method was applied to the distinc tion of isomeric monoterpene pairs whose mass spectra are nearly identical. It is shown that the IKE spectra can be used for such isomers, which was exemplified by the case of borneol and iso-borneol.

The mass spectra of fifteen diterpenoids belonging to the new carbon skeletons of verrucosane, neoverrucosane and homoverrucosane are examined. From their spectra the relationship between fragmentation patterns and substituted modes of these diterpenoids is discussed.

Ammonia and isobutane chemical ionization mass spectra of the intact flavone glycosides are described. The protonated molecular ion(MH+) are peaks very weak and glycosidic bond cleavage is observed as the major fragmentation pathway. Consequently, the mass spectra exihibit the protonated aglycone ions as the base peak and the various sugar-derived ions.

Mass spectra of three naturally occurrig ent-15-ketokauranoids, (I), (III)and(IV), and their derivatives, (II)and(V), were measured and their characteristic fragmentations were discussed.

Mass spectra of some o-hydroxyacetophenones were studied. The fragmentation is discussed on the basis of high resolution data and deuterium labeling. The resulting fragment patterns are clearly influenced by the position of the methoxy group.It is shown that the significant structural information can be obtained from mass spectra of o-hydroxyacetophenones.

Mass spectra of pterocarpan derivatives (I∼VII) are recorded in Figs. 1∼5 and Tables 1∼6. The major fragmentation pathways of these compounds are shown in Scheme1. The results illustrate that the observed fragmentation patterns are of considerable utility in the application of mass spectro metry to structure elucidation in this series.

Ion kinetic energy(IKE)spectrum of β-phenylethyl cinnamate is presented(Fig. 2). The molecularion of β-phenylethyl cinnamate undergoes several decompositions, three of which are the loss of H2O, COOH and HCOOH. To study these processes, the high resolution mass spectrometry and IKE spectrum of. β-phenylethyl cinnamate were studied. Some of the fragmentation pathways of β-phenylethyl cinnamate are shown in Fig. 6.