The determination of pentachlorophenol and tetrachlorophenols in wadden sediment and clams (Mya arenaria) using triethylsulfonium hydroxide for extraction and pyrolytic ethylation.

A method to determine the concentration of pentachlorophenol and tetrachlorophenols in wadden sediments and clams is described. This method involves the extraction of lyophilized specimens with toluene under acidic conditions and the back extraction of the chlorophenols into a methanol/water solution of triethylsulfonium hydroxide. Upon injection of the methanol/water phase into the gaschromatograph a pyrolytic ethylation is performed and the ethylethers of pentachlorophenol and tetrachlorophenols formed thereby are separated in quartz capillary columns and detected by an electron capture detector. Using tribromophenol as internal standard the recovery rates for the chlorophenols were within the range of 76.7 and 98.8%. The method described does not require any evaporation or chromatographic clean-up steps. The detection limit was found to be 2 nmol/kg (approximately 500 ng/kg) for sediment and 0.1 mumol/kg (approximately 25 micrograms/kg) for clams. Its accuracy was verified by gaschromatography-mass spectrometry experiments.