Kinetic Spectrophotometric Determination of Nanogram Levels of Manganese (II) by Azo Dye – Potassium Periodate – 1,10-Phenanthroline System

Manganese is an essential microelement for the human body. In normal conditions it plays an important role in bone and tissue formation (normal growth), normal reproductive functions, and carbohydrate and lipid metabolism. The diet is the basic source of the metal. A daily dietary intake of 2 to 5 mg is estimated to be adequate for adults. Manganese deficiency in humans is related to delayed blood coagulation and hypercholesterolaemia. The metal may be considered toxic when dietary intake is significantly higher . Hence, sensitive and selective methods for determination of manganese in foodstuffs, drinking waters and drinks are of great interest. Many kinetic methods have been reported for the determination of manganese (II), based on its catalytic effect on the oxidation of organic compounds most frequently with hydrogen peroxide and the periodate ion 2−12. However, most of these methods lack sufficient sensitivity for determining manganese (II) at or below ng cm−3 levels. Among the most sensitive methods described so far are: (a) the method