Catalytic kinetic spectrophotometric determination of trace molybdenum in gangue

A new kinetic spectrophotometric method for the determination of trace amounts of molybdenum has been proposed.It was based on the molybdenum inhibited coloring reaction of methyl green oxidized by hydrogen peroxide in the sodium borate-sulphuric acid medium.The optimum conditions and kinetic parameters were investigated.The apparent activation energy of inhibition reaction is 14.64 kJ/mol and the apparent reaction rate is 3.77×10-4/s.The linear range of determination of molybdenum was 0~0.5 mg/L and the detection limit was 3.82 μg/L.The apparent molar absorption coefficient is 5.357×105 L · mol-1 · cm-1.The method has been used for the determination of trace amounts of molybdenum in gangue.The relative standard deviations were 2.3% ~3.1% and the recoveries were 96.0%~104% with satisfactory results.