Analytical Method for 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin in Sea Foods

Abstract

The herbicides, 2, 4-D, 2, 4, 5-T, and PCP, which are drived from polychlorinated phenols, are usually contaminated with polychlorinated dibenzo-p-dioxins, and tetrachlorodibenzo-p-dioxin (TCDD) has been given a special attention for its high toxicity to mammals. An improved analytical method for TCDD in sea foods by gas chromatography with ECD and subsequent utilization of mass spectrometer was established. Samples were first hydrolyzed directly with alkali to remove organochlorine pesticides as well as esterified lipid materials. After the extraction of TCDD with hexane, nonsaponifiable materials contained in the extract was removed by treatment with concentrated sulfuric acid. PCB, which still overlap with TCDD in gas chromatographic analysis, can be removed by alumina column chromatography. Samples for which the cleanup by alumina column chromatography was insufficient were further subjected to Florisil column chromatography. Recovery of TCDD added to chopped fish samples by the present method was in the range of 85.4 to 92.5% and the detection limit was about 1.5 ppb by the above mentioned gas chromatography. Since the detection limit is not necessarily sufficient for the environmental monitoring of TCDD, mass fragmentography was employed for further elevation of sensitivity. Thus, 10 ppt of TCDD was become detectable from sea foods.