Untargeted screening of secondary fungal metabolites in crude extracts and samples from mouldy indoor environments by time-of-flight mass spectrometry

Nowadays, complaints about poor indoor air quality have become common. The variety of indoor-air health problems include chronic fatigue, allergy, skin and eye irritation and can be caused by several factors including fungi and their metabolites present in a building. The objective of this study was to establish a simple method for untargeted analysis of secondary fungal metabolites in indoor environments. As a detection technique, it was opted for time-of-flight mass spectrometry, as it provided high sensitivity and mass accuracy in full scan acquisition mode. The method was firstly applied to fungal cultures, namely Penicillium brevicompactum and Chaetomium murorum, which were isolated from mouldy houses and grown on building materials in laboratory conditions. Following the proposed strategy based on accurate mass measurement and post-acquisition data processing using statistical tools, a number of metabolites were identified. Subsequently, samples from mouldy inhabited buildings were screened using the developed method.