Studies of organohalogens in cod brain tissues by neutron activation analysis (Gadus morhua).

摘要

Atlantic cod fish (Gadus morhua) has always been an important source of food as well as of income for people living in Atlantic Canada. The accumulation of organochlorines in this species could lead to toxic effects. The main objective of this thesis work was to study the levels of extractable organohalogen compounds present in cod brain tissues.; Two different solvent extraction methods were studied in this work. One of the systems used hexane: isopropanol (3:2) and the other a mixture of hexane: ethyl acetate: methanol: water. The second method provided the best separation and it was used for the extraction of cod brain lipids. This was followed by a fractionation of the extract into different lipid classes using size exclusion chromatography, solid phase extraction, and high performance liquid chromatography. Neutron activation analysis was used for the direct measurement of the halogen content. The quantification of the uncertainty in the NAA measurements of the halogens was also investigated in detail. Expanded uncertainty values of 10%, 12% and 15% were obtained for chlorine, bromine and iodine, respectively. (Abstract shortened by UMI.)