Elucidation of the mass fragmentation pathways of potato glycoalkaloids and aglycons using Orbitrap mass spectrometry

摘要

The mass fragmentation of potato glycoalkaloids, α-solanine and α-chaconine, and the aglycons, demissidine and solasodine were studied using the Orbitrap Fourier transform (FT) mass spectrometer. Using the linear ion trap (LIT) mass spectrometry, multistage collisional-induced dissociation (CID) experiments (MS~n) on the [M+ H]~+ precursor ions were performed to aid the elucidation of the mass fragmentation pathways. In addition, higher energy collisional-induced dissociation (HCD) mass spectra were generated for these toxins at a high resolution setting [100 000 FWHM (full width at half maximum)] using the Orbitrap. This hybrid mass spectrometry instrumentation was exploited to produce MS~3 spectra by selecting MS~2 product ions, generated using LIT MS, and fragmentation using HCD. The accurate mass data in the MS~3 spectra aided the confirmation of proposed product ion formulae. The precursor and product ions from glycoalkaloids lost up to four sugars from different regions during MS ~n experiments.Mass fragmentation of the six-ring aglycons were similar, generating major product ions that resulted from cleavages at the B-rings and E-rings.