Quantitation of ergosterol in river sediment by liquid chromatography

The ergosterol content of a river sediment can be used as an indicator of fungal activity. A method is developed for the extraction and determination of ergosterol in river sediment as part of a study to assess the correlation between fungal activity and biodegradation of pyrene, which is an environmental pollutant. This method is based on saponification and the liquid-liquid extraction of ergosterol by ethyl acetate. Quantitation and detection are performed isocratically by liquid chromatography on a 5-microm Hypersil C18 column with methanol-acetonitrile (80:20, v/v) as the mobile phase and detection at 282 nm. The detection limit is 50 ng/mL ergosterol, which is equivalent to 0.1 microg/g. The recovery of ergosterol at a concentration level in the range of 2 to 12 microg/mL is 91.7% +/- 3.1% without interferences. This method is applied in order to successfully quantitate the ergosterol content in a river sediment with or without a fungus supply.