Catalytic kinetic spectrophotometric determination of iron（Ⅲ） in iron（Ⅲ）-phenosafranine-potassium bromate system
XIE Jian-ying*1， CHEN Zong-bao1， LEI Ming-jian2
1. College of Chemistry and Chemical Engineering, Shangrao Normal College, Shangrao 334001, China; 2. No.226 Geological Team, Jiangxi Bureau of Coal Geological Exploration,Pingxiang 337000, China
Abstract：In HAc-NaAc buffer solution medium at pH 4.0, trace iron（Ⅲ）could catalyze the fading reaction of phenosafranine oxidized by potassium bromate under the sensitivity enhancing function of polyvinyl alcohol （PVA） surfactant. On the basis of this henomenon, a new catalytic kinetic spectrophotometric determination of trace iron was established. The related determination conditions and the dosage of reagents were optimized. The effect of other ions on the determination was investigated. Under the optimal experimental conditions, the apparent activation energy of catalytic fading reaction was 84.03 kJ/mol, the linear range of method was 0.02-0.32 μg/mL, and the detection limit of iron（Ⅲ） was 6.6×10-7 g/L. The proposed method was applied to the determination of iron in glass and ceramic sample. The relative standard deviations （RSD） were 2.6 %-4.1 %, and the recoveries of standard addition were 94 %-102 %.
