Extraction and purification of a new compound containing selenium and mercury accumulated in dolphin liver

Dolphins sometimes accumulate Hg and Se as high as 100 μg/g or more in their livers. In the present study, a compound containing Hg and Se in a dolphin liver was extracted and purified by cation exchange, gel filtration, and paper, anion exchange, and chelate chromatographies. The Hg and Se contents in every fraction were determined by atomic absorption spectrometry using the palladium addition method. In all chromatographic fractions Hg and Se appeared in the 1∶1 molar ratio. The purified compound is water-soluble, with a molecular weight of less than 1000, and contains amino-groups, as well as Hg and Se at a 1∶1 molar ratio. Mercury in the compound is not removed by the chelate resin, indicating that the metal is not ionic and is tightly bound.