Figure 3.

The fragmentation pathways of spirostanol saponins, taking purpureagitoside as the example: the ion at m/z 739 was the molecular ion [M-H]⁻, the ion at m/z 577 [M-H-C₆H₁₀O₅]⁻ was produced by the loss of a hexose unit (Glc, 162 Da), the fragment ion at m/z 415 [M-H-2C₆H₁₀O₅]⁻ could be explained by ejecting a pentose unit (Gal, 162 Da) from the ion at m/z 577, the fragment ion at m/z 273 was formed by the cleavage of the E-ring, and the fragmentation of m/z 255 was obtained by the fragmentation m/z 273 to lose a water molecule.