Determination of Illudin S in Omphalotus guepiniformis and Foods that Caused Food Poisoning by Liquid Chromatography with Tandem Mass Spectrometry

A simple method was developed for determination of illudin S in fungi (Omphalotus guepiniformis: poisonous mushroom) and a food that caused food poisoning, using liquid chromatography tandem mass spectrometry (LC/MS/MS). Illudin S in fungi and the food that caused food poisoning was extracted with methanol and then cleaned up with an Oasis HLB cartridge. LC separation was performed with an octadecylated silica column (Inertsil ODS-3, 2.1 mm i.d.x150 mm) and a mobile phase of 0.1% formic acid-methanol (7: 3) at a flow rate 0.2 mL/min. Mass spectral acquisition was performed in the positive mode and illudin S was targeted using multiple reaction monitoring (MRM) with electrospray ionization (ESI). The recoveries of illudin S were 84-94% from edible fungi (Lentinula edodes, Pleurotus ostreatus and Panellus serotinus). The detection limits of illudin S in the fungi (L. edodes, P. ostreatus and P. serotinus) were 0.08-0.10 mu g/g respectively. Illudin S was detected in the food that caused food poisoning at the level of 2.0 and 15.1 mu g/g in the soup and fungi, respectively. The recovery of illudin S from a mushroom soup (cooked at 100 degree C for 10 min) sample which simulated food poisoning was 74.8%. These results indicate that the developed method is suitable for the determination of illudin S in fungi (O. guepiniformis) and foods that caused food poisoning.