DETERMINATION OF PART-PER-TRILLION CONCENTRATIONS OF 2,3,7,8-TETRACHLORODIBENZO-PARA-DIOXIN IN FISH

An analytical procedure has been developed and utilized for the determination of approximately 10 to 100 parts per trillion (10-12 g/g) concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in fish. The technique involves digestion and extraction of the matrix followed by a series of adsorbent, and chemically-modified adsorbent, liquid column chromatographic clean-up steps. A final “residue polishing” step via elevated temperature reversed-phase high performance liquid chromatography is applied prior to detection by multiple ion mode gas chromatography-mass spectrometry. Using 13C-labeled TCDD as an internal standard and carrier, the procedure has been validated for rainbow trout from approximately 10 to 100 ppt TCDD. Relative to this range, TCDD recovery is 75% ± 25 %, and the precision of a single determination at the 95 % confidence level (2σ ) is ±20% relative at 50 ppt TCDD concentration. © 1979, American Chemical Society. All rights reserved.