The most toxic mushrooms are of the Amanita species (A. verosa, A. verna, and A. phalloides). Just one mushroom cap can be fatal if ingested. The toxins in these mushrooms are identied as cyclic peptides. The structure of α-amanitin is shown in Figure 14.5, and careful isolation from the amanita mushroom is shown as follows:
Extract with 1:1 v/ v methanol-water
Retain the supernatant➩
Column chromatography Powdered cellulose mixed with acetone Solvent: 20:6:5:1 parts of methyl ethyl ketone, acetone, water, and butanol➩
α-Amanitin and β-Amanitin
These compounds are highly toxic and can destroy the liver. Because of the concerns over toxicity, forensic analysis of α-amanitin and β-amanitin in human plasma by liquid chromatography-mass spectrometry has been investigated. Good separation has been achieved using high-performance liquid chromatography-mass spectrometry (LC-MS) and LC-tandem mass spectrometry (LC-MS-MS) analysis. A Discovery DSC 18 column was used, eluting rst with water and then increasing amounts of methanol. The subsequent extract, after evaporation and reconstitution
in mobile phase solution, was subjected to LC-MS analysis with a conventional octadecyl LC separation column. In the tandem mass spectrum, selected ion monitoring of α-amanitin and β-amanitin at m/ z 919-921 and m/ z 920-922, respectively, generates good separation of both amanitin peaks (Figure 14.6).