Kinetic Spectrophotometric Determination of Trace Selenium (Ⅳ) by Its Catalytic Effect on the Reduction of Arsenazo Ⅰ with Sodium Hypophosphite in Micellar Media
A simple and sensitive kinetic spectrophotometric method for the determination of trace selenium (Ⅳ) based on its catalytic effect on the reduction arsenazo Ⅰ (AsA Ⅰ) with sodium hypophosphite (NaH2PO2) in a solution of 0.02 mol/L sulfuric acid and in the presence of cationic micellar media is described.The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of AsA Ⅰ at 500 nm after a fixed time (8 min).The decrease in the absorbance of AsA Ⅰ is proportional to the concentration of Se(Ⅳ) in the range 0.18-1.0 μg/L with a fixed time of 4-8 min from the initiation of the reaction.The limit of detection is 0.053 μg/L Se(Ⅳ).The influence of the factors such as acidity,concentration of reactants,reactive time,temperature and co-existing ions on the reaction is discussed.The optimum reaction conditions of reaction are established and some kinetic parameters are determined; the apparent activation energy of catalytic reaction is 45.69 kJ/mol.The relative standard deviation for eleven replicate determination of 0.02,and 0.01 μg/25mL Se(Ⅳ) was 2.3 % and 2.4 %,respectively.Combined with sulphydryl dextrane gel (SDG)separation and enriching,the method has been successfully applied to the determination of Se (Ⅳ) in foodstuff and human hair samples with the relative standard deviation of 2.7 %-5.8 % and the recovery of 96.0 %-101.5 %,the results are in good agreement with those provided by ICP-AES method.
Selenium (Ⅳ) kinetic spectrophotometry arsenazo Ⅰ sodium hypophosphite micellar media
Zhirong Zhou Lizhen Zhang
College of Public Health,Guangdong Pharmaceutical University,Guangzhou,China The Clinic Attached to Guangdong Pharmaceutical University,Guangzhou,China
国际会议
Conference on Environmental Pollution and Public Health (2012年环境污染与大众健康学术会议(CEPPH2012))
上海
英文
186-190
2012-08-09（万方平台首次上网日期，不代表论文的发表时间）