Simple and sensitive determination of hepatic copper by use of an extractive catalytic method

For determination of copper in liver tissue and in liver biopsy samples an extractive catalytic determination is proposed. After digestion of the liver samples with nitric acid, copper is extracted as the salicylate-pyridine complex into chloroform and determined catalytically directly in the organic extract by addition of ethanolic solutions of sulphanilic acid, pyridine and hydrogen peroxide. Copper can be determined in the range from 10 to 350 ppm (dry weight basis) with a relative standard deviation of 5-15%. The method enables copper to be determined in liver biopsy samples of about 5 mg dry weight by use of a simple spectrophotometer, and can be used in diagnosis of Wilson's disease.