Negative ion tandem mass spectrometry of prenylated fungal metabolites and their derivatives

Liquid chromatography negative ion electrospray ionisation tandem mass spectrometry has been used for characterisation of naturally occurring prenylated fungal metabolites and synthetic derivatives. The fragmentation studies allow an elucidation of the decomposition pathways for these compounds. It could be shown, that the prenyl side chain is degraded by successive radical losses of C₅ units. Both the benzoquinones and the phenolic derivatives display significant key ions comprising the aromatic ring. In some cases, the formation of significant oxygen-free key ions could be evidenced by high-resolution MS/MS measurements. Furthermore, the different types of basic skeletons, benzoquinones and phenol type as well as cyclic prenylated compounds, can be differentiated by their MS/MS behaviour.