Determination of micro antimony by reverse flow injection catalytic kinetic spectrophotometry

A new method of flow injection catalytic kinetic spectrophotometry is developed for the determination of micro antimony(Ⅲ).It is based on the anticatalytic property effects of Sb(Ⅲ)) on the oxidation reaction between 2-[2′-(5-nitropyridylazo)]-1,8-dihydroxynaphthalene-3,6-disulfonic acid(5-NO2-PACA) and potassium bromate in phosphoric acid medium.The linear range of determination is 0-0.36 μg/mL.The detection limit is 9.6×10-6 g/L.The proposed method has been applied to the determination of Sb(Ⅲ) in environmental water samples such as mountain spring water and rain water,with the recovery of 92.5%,107% and RSD of 0.75% and 1.0% respectively.The results are in good agreement with those of atomic absorption spectrometry.