Determination of ultra trace amount manganese (II) in water samples with the 1-(2-PyridylAzo)-2-Naphthol, (PAN) by the bromate ion in sulfuric acid with kinetic spectrophotometric method

A new kinetic spectrophotometic method for the determination of trace amount manganese(II) in Tea real samples has been described based on it s the catalytic effect on the oxidations of 1 - (2 – Pyridyl Azo) - 2 - Naphthol, (PAN), by potassium bromated in sulfuric acid. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 547.5 nm. Under the optimum conditions of 0.2 molL-1 sulfuric acid, 1.0 × 10-4 molL-1, 1 - (2 - PyridylAzo) - 2 - Naphthol, (PAN), 1mL of potassium bromate 0.11 mol L-1 at 35oC, calibration graph in the rang of 0.001-0.06 μg mL-1 manganese (II). Concentration was obtained with detection limit of 0.23 ng mL-1 by the fixed-time method of 4.5 min. The relative standard deviation for 0.05μg mL-1 manganese(II) is %90. No serious interference was identified. The applicability of the method was demonstrated by the determination of the manganese (II) in Water, Vegetables and blood samples.