Electron impact, chemical ionization and field desorption mass spectrometry of substituted dihydroxyphenyl-benzodioxins isolated from insect cuticle. Occurrence of thermal decomposition and oligomerization reactions in the mass spectrometer.

The electron impact, field desorption and chemical ionization mass spectra of seven dihydroxyphenyl-benzodioxins isolated from insect cuticle are discussed. Reproducible electron impact and chemical ionization spectra are obtained as a result of thermal decomposition and either electron impact or chemical ionization. In some of the chemical ionization spectra dimerization of the thermal degradation products is observed. Structure determination is possible based upon the electron impact and field desorption spectra.