Catalytic kinetic spectrophotometric determination of trace ironIII with iron-potassium bromate-chlorophosphonazo-mA system

A new catalytic kinetic spectrophotometric method for the determination of trace ironⅢ was developed.It was based on the catalytic effect of ironⅢ on the fading reaction of chlorophosphonazo-mA oxidized by potassium bromate in sulphuric acid medium.The detection limit of this method was 1.27×10~(-9)(g/mL) for ironⅢ and Beer's law was obeyed in the range of 0.01-1.0 μg/10 mL.The RSD and recovery were 1.9%-2.4% and 98%-103%,respectively.The method has been used for determining ironⅢ in water and hair samples with satisfactory results.