Phenolic compounds interfere in the estimation of copper by diethyldithiocarbamate method

Abstract

For the estimation of copper, diethyldithiocarbamate method is most commonly employed in various laboratories where atomic absorption spectrophotometer is not available. The prevalence rate of gastrointestinal malignancies is very high in Kashmir as compared to other parts of the world. We could find high serum copper levels in gastrointestinal tract cancer. Intake of salted tea, prepared in copper vessel, is very common in Kashmir. Such tea samples showed copper value as 3168.9 (S.D. 700.5) μg/dl estimated by diethyldithiocarbamate method. When these samples analysed by atomic absorption spectrophotometer, the copper levels were just 9% as reported by colorimetric method. Various black salted tea samples were prepared in the laboratory in glass vessel. The mean copper was 1115.0 (S.D. 350.4) μg/dl. After addition of milk, the values were reduced by 50%. Nine phenolic compounds showed varying amount of copper by colorimetric method and no copper could be detected by atomic absorption spectrophotometer. Phenolic compounds present in tea leaves interfere in the estimation of copper by diethyldithiocarbamate method. It is suggested that diethyldithiocarbamate colorimetric method for copper estimation is not suitable for solutions containing phenolic compounds.