Low-resolution multiple ion detection gas chromatographic-mass spectrometric comparison of six extraction-cleanup methods for determining 2,3,7,8-tetrachlorodibenzo-p-dioxin in fish

Six laboratories participated in a study of six extraction-cleanup procedures for determining 2,3,7,8-tetrachlorobenzo-p-dioxin (TCDD) in fish. Six samples (three unfortified and three fortified with TCDD) were sent to each laboratory for extraction-cleanup according to the procedure(s) in use by each laboratory at that time. Sample extracts were returned to the Bureau of Foods, Food and Drug Administration (BF/FDA), for examination by capillary gas chromatography-low-resolution multiple ion detection mass spectrometry (GC-MS), using 12 ions. In addition, electron capture GC and full-scan GC-MS were employed to give additional measures of cleanup efficiency. Under the GC-MS conditions used by BF/FDA to examine the sample extracts, the Dow and Fish and Wildlife Service procedures were most efficient. The ranking of the other procedures, in order of decreasing efficiency, was New York State Department of Health, FDA, Environmental Protection Agency (EPA) neutral, and EPA acid-base.