Determination of ergosterol on mouldy building materials using isotope dilution and gas chromatography-tandem mass spectrometry

Ergosterol content of building materials was quantified using gas chromatog raphy-tandem mass spectrometry (GC-MS-MS) in an ion trap with external ioni sation. Hydrolysing the samples by classic extraction at 85 degreesC for 90 min in vials was faster, more precise and safer than microwave assisted ex traction. [4-H-2(2)]ergosterol was synthesised and used as internal standar d, giving method standard deviation of 5-10% from 10 to 30 ng to 10-15 mug ergosterol in the sample. The use of GC-MS-MS meant that no solid-phase ext raction clean-up was needed, so one person could easily prepare 40-80 sampl es per day. (C) 2000 Elsevier Science BN. All rights reserved.