Kinetic, Spectrophotornetric Determination of Nanogram Levels of Manganese(II) Using Catalytic Azo Dye-Potassium Periodate-1,10-Phenanthroline System

摘要

The catalytic effect of manganese(II) on the oxidation of the dye, sodium salt of 4-(2-hydroxynaphth-l-ylazo)benzenesulfonic acid, with potassium, periodate in the presence of 1,10-phenanthroline in weakly acidic media was studied. The reaction was followed spectrophotomet-rically by measuring the decrease in the absorbance of the dye at A = 483 nm. Under the optimum conditions Mn(II) concentration within the range of 0.08-4 ng an"3 could be determined by the fixed-time method with a detection limit of 0.025 ng cm"3. The method was applied for the determination of manganese content in tomatoes, aubergine, white radish, and French beans. The results showed a good agreement with those obtained by atomic absorption spectrophotometry.