Determination of trace Vanadium by flow injection catalytic-kinetic spectrophotometry

A new method is developed for the determinetion of trace vanadium by flow-injection catalytic-kinetic spectrophotometry.It is based on the catalytic effect of V(Ⅴ) on the redox reaction between 2-(5-nitro-2-pyridylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid(5-NO2-PACA) and potassium bromate in phosphoric acid.This method is easy to be operated and quick.The linear range of determination is 0.2～2.2 μg/mL and the linear regression equation is ΔA=-0.004+2.63ρ(μg/mL) with correlation cofficient r of 0.9988.The detection limit is 4.1×10-6 g/L.The method has been used for the determination of trace vanadium in water samples with satisfactory results.