Mass spectrometry of Alternaria mali toxins and related cyclodepsipeptides.

The structures of AM-toxins I, II and III, host specific phytotoxic metabolites of Alternaria mali, can be readily deduced from low and high resolution mass spectral data, since the amino acids and their sequences are demonstrated by this technique. Additionally, the general fragmentation of these compounds by electron impact is discussed by comparing the spectra of analogous synthetic compounds.