Kinetic, spectrophotometric determination of nanogram levels of manganese(II) using catalytic azo dye—potassium periodate—1,10-phenanthroline system

Abstract

AbstractThe catalytic effect of manganese(II) on the oxidation of the dye, sodium salt of 4-(2-hydroxynaphth-1-ylazo)benzenesulfonic acid, with potassium periodate in the presence of 1,10-phenanthroline in weakly acidic media was studied. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at λ = 483 nm. Under the optimum conditions Mn(II) concentration within the range of 0.08–4 ng cm−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.