Determination of ergosterol as an indicator of fungal biomass in various samples using non-discriminating flash pyrolysis

Abstract

Ergosterol is the major sterol constituent of most fungi. Since it is present in negligible amounts in higher plants, it can be used as a chemical marker for the presence of fungal contamination. A number of different ergosterol assays have been developed for the quantification of fungi in various samples. The paper presents the development of a new method for ergosterol detection based on the combination of non-discriminating flash pyrolysis with gas chromatography/mass spectrometry (Py-GC/MS). The design of the non-discriminating Py-GC/MS systems assures efficient transfer of high-molecular-weight pyrolysis products to the GC column for separation, followed by analyte detection by MS. The method was tested on different types of samples, including baker's yeast ( Saccharomyces cerevisiae), moldy bread, indoor dust, and a leaf infected with powdery mildew. Ergosterol was detected in all these samples at levels ranging from ∼4 mg/g for the baker's yeast to ∼6 μg/g for household dust. The main benefits of non-discriminating pyrolysis over other techniques include elimination of the need for sample preparation, small sample size required and short analysis time.