A new method for the isolation of methylmercury from biological tissues and its determination at the parts-per-milliard level by gas chromatography.

A new method has been developed for the isolation of methylmercury from biological tissue. It is based on the volatilization of methylmercury cyanide formed in the reaction of methylmercury in the tissue with hydrocyanic acid released in the interaction of potassium hexacyanoferrate(II) with sulphuric acid at elevated temperature. The methylmercury cyanide released is captured on cysteine paper in a microdiffusion cell. The isolated methylmercury is set free with hydrochloric acid, extracted into benzene and determined by gas chromatography. A special closed micro-extractor is used for the final extraction into benzene for samples containing the lowest levels of methylmercury. The method can be used for a wide range of samples and concentrations (including background levels). The simplicity of the method makes it suitable for routine application.