Gas-liquid chromatographic screening method for determination of methyl mercury in tuna and swordfish

A rapid screening method has been developed for determining methyl mercury in tuna and swordfish. Fish tissue is blended with acidic KBr solution to release methyl mercury, which is then extracted into methylene chloride. After cleanup by partitioning with cysteine, the methyl mercury is extracted into toluene and determined by gas-liquid chromatography. The proposed method compares favorably with the official AOAC atomic absorption method.