Determination of Trace Manganese By Catalytic Kinetic Spectrophotometry With NP-7 As Sensitizer

A new method for the determination of trace manganese by catalytic Kinetic spectrophotometry was described, which was based on the manganese(Ⅱ)catalyzed oxidation of arsenazo(Ⅲ) by potassium periodate in HAc-NaAc medium in the presence of NP-7. The best conditions were determined by orthogonal experiment, with detection limit 1.6×10-6 g/L, concentration range 0.12～0.68 μg/25 mL of manganese(Ⅱ). The method was applied to the determination of trace manganese from Co-Mn catalyst with satisfactory results, which was in accordance with atom absorptive spectrophotometry, with relative error 3.83%, maximum relative standard deviation 3.66% and recovery rate 95.5 % 105.0%.