Validation of Sequential Cathodic-anodic Stripping Voltammetric Determination of Ultratrace Level of Copper, Lead, Cadmium, Zinc, and Selenium in Milk and Dairy Products of Iran

The concentrations of Pb, Cd, Cu, Zn and Se metal ions in milk and dairy products (pasteurized milk, doogh, cheese and yoghurt) were determined with differential pulse anodic and cathodic stripping voltammetry technique at HMDE electrode. For more accurate and selective metal ions determination the samples were digested by dryness-HNO3ὤ軣 H2O2 heat digestion method. The concentration linear ranges of Pb, Cd, Zn, Cu and Se in fermented milk sample were in the range of 0.5-200, 0.3-220, 0.1-500, 0.1-450, and 0.4-120 ppb, respectively. The recovery for metal ions in all samples was in the range of 89 to 99%. The intermetallic effect of metal ions was omitted by change of pH. This study shows that nearly in all cases the concentration of the measured amounts are lower than the international permissible limits and there is no health threatening concern due to the consumption of milk and dairy products in Iran.