Determination of Trace Manganese (VII) by Resonance Light Scattering Method with Crystal Violet

Based on the ability of oxidizability of trace manganese (VII) can oxidize the I- into form I₃^- with the Media of hydrochloric acid solution, and the crystal violet can react with I₃^- to form of CV-I₃ ion association molecule. Thus a new resonance light scattering (RLS) method for the determination of trace manganese (VII) was developed. And the affecting factors of intensity of RLS and the optimum conditions of the reaction systems were investigated. The maximum RLS peak was located at 320 nm. The detection limit and the linear range of manganese (VII) were 1.79 × 10^-7g · L^-1 and 0~0.62μg · mL^-1, respectively. It can be operated conveniently at room temperature. The satisfactory results were achieved in employing this method into the determination of manganese (VII) in environmental water samples. The recovery of environmental water was 99.2%~100.4%. A pilot study on the mechanism of reaction was given.