View article

Underivatized pyrrolizidine alkaloids (PAs) from natural sources (plants and insects) were analysed by capillary gas chromatography-mass spectrometry. GC-MS data (retention indices and [M]⁺) of ca 100 PAs separated on different fused-silica columns in two laboratories are presented and compared. The results suggest that polydimethylsiloxane coated columns (OV-1, DB-1) are well suited for comparative studies in different laboratories. Separation of PAs using either OV-1 or DB-1 in different laboratories even under slightly different conditions revealed almost identical RIs. Application of these columns and the combination of RI, [M]⁺ and group-specific MS fragmentation allows in many cases the unequivocal assignment of PAs from complex mixtures even in the presence of different geometrical isomers. Furthermore, it encourages a reliable comparison and exchange of data between laboratories.