Ergosterol as an indicator of mould growth on building materials.

Ergosterol was used as a specific indicator of fungal biomass to determine and assess mould growth on damp building material. The samples were saponified, cleaned up on a silica gel column and the sterols silylated and analysed by gas chromatography and mass spectrometry in MS/MS mode. Ninety-one samples of building materials from damp rooms were analysed including plaster, plaster/paint, paint, wood-chip wallpaper and paper wall covering. The concentrations of ergosterol ranged from 0.1 to 130 microg/g dry mass and depended on carbon content of the material. The highest concentrations were determined for wallpaper, the lowest for plaster and intermediate ones for paint. Based on ergosterol content and inspection of the room during sampling a rough classification of mould infestation is presented. The applicability of the ergosterol method was further tested in two case studies on the spatial distribution of fungi on damp walls and irregular distributions were found. With few exceptions the concentration of ergosterol in building materials was found to be a suitable indicator to estimate fungal biomass.