Application of head-space solid-phase microextraction for the analysis of volatile metabolites emitted by Penicillium species

Abstract

Head-space solid-phase microextraction (HS-SPME) has been used to collect volatile organic compounds (VOCs) emitted from fungi of the genus Penicillium. Gas chromatography combined with mass spectrometry (GC-MS) was employed for the analysis of the profiles of volatile metabolites characteristic for each species. The results obtained by HS-SPME compared favourably with those obtained by Tenax adsorption. The following characteristic metabolites were detected: isopentyl alcohol, 1-octene-3-ol, 3-octanone, 3-octanol, 2-methylisoborneol and geosmin, together with the not previously reported acetates of 1-octene-3-ol and 3-octanol. Further, several mono- and sesquiterpene hydrocarbons and alcohols were identified, many of those for the first time from Penicillium species. The growth conditions were found to be of major importance for the quantitative aspects. Distribution coefficients between the fibre coating and air were determined for some typical fungal metabolites using polyacrylate and polydimethylsiloxane as fibre coatings. No significant differences in the results for the two fibre coatings were observed for non-polar to slightly polar compounds, whereas the more polar compounds were better extracted by the polyacrylate fibre coating. However, the equilibration times are longer with this fibre coating. Increasing responses were observed with decreasing volatility of the compounds for both types of fibre coating. Being a rapid, simple and practically non-interfering technique, HS-SPME has a great potential use in the analysis of biogenic VOC emissions, including chemotaxonomical studies.