Development of a method for determining illudin S in food by gas chromatography-mass spectrometry

Abstract

A method was developed for determining illudin S, a naturally occurring toxin in the mushroom Lampteromyces japonicus in food samples with the use of gas chromatography-mass spectrometry (GC-MS). Samples of a model food, 'Ton-jiru' (miso soup), were spiked with authentic illudin S, which was then extracted from the samples by a two-step solvent extraction with ethyl acetate and acetonitrile-n-hexane, followed by solid phase extraction using a normal phase Bond Elut SI cartridge. The recovery of illudin S from the samples was in the range of 61-74%. Illudin S was identified by its GC retention time and both electron and chemical ionization mass spectra. In the splitless injection mode, the calibration curves for peak area ratio of illudin S to anthracene (internal standard) were linear, in the range from 150 pg to 150 ng with correlation coefficients exceeding 0.997, and the detection limit was 36 pg per injection volume (1 μl).