阻抑过氧化氢氧化偶氮胂I褪色反应动力学光度法测定痕量锌  

Kinetic spectrophotometric determination of trace zinc (Ⅱ) by its inhibitory effect on the oxidation of arsenazo I with hydrogen peroxide

作　　者：蔡朝锦[1] 陈聪[1] 周之荣[1] 易秀银[1] 林耀盛[1] 

机构地区：[1]广东药学院公共卫生学院,广州510240

出　　处：《食品科技》2010年第4期269-272,276,共5页Food Science and Technology

基　　金：教育部预防医学特色专业建设点(教高函[2008]21号);中国高等教育学会"十一五"教育科学研究专项课题(粤高教学会[2007]5号);广东省高等学校人才引进专项资金项目(粤财教[2009]109号);广东药学院科研基金项目(2007GGW03)

摘　　要：基于pH=10.3NH3-NH4Cl缓冲介质中,反应温度为100℃时,痕量锌(II)阻抑H2O2氧化偶氮胂I(AsAI)的褪色反应,建立了测定痕量锌(II)的阻抑反应动力学光度法。在固定加热时间段(4min10s)后,于515nm处测定AsAI的吸光度增加值,监控反应速率。方法检出限为1.72μg/L,校准曲线的浓度线性范围为0.0～2.0μg/25mL。讨论了酸度、反应物浓度、温度、反应时间、干扰离子等因数的影响,研究了反应的最佳条件,并测定了一些动力学参数,阻抑反应的表观活化能为84.00kJ/mol。方法用于奶粉样品中痕量锌(II)的测定,相对标准偏差为2.4%～3.1%,加标回收率为98.2%～103.2%。A spectrophotometric method for the determination of zinc（Ⅱ） is described,based on its inhibitory effect on the oxidation reaction of acid arsenazo I with hydrogen peroxide in pH =10.3 NH3-NH4Cl buffer medium at 100 ℃.The reaction rate is monitored spectrophotometrically by measuring the increase in the absorbance of arsenazo I at 515 nm after a fixed heating time（4 min,10 s）.The calibration curve for the recommended method is linear in the concentration range over 0.0～2.0 μg/25 mL zinc（Ⅱ） and the detection limit of the method is 1.72 μg/L.The influence of the factors such as acidity,concentration of reactants,reaction time,temperature and co-existing ions on the reaction is discussed.The optimum conditions of reaction are established and some kinetic parameters are determined.The apparent activation energy of catalytic reaction is 84.00 kJ/mol.The method has been successfully applied for the determination of trace zinc（Ⅱ） in some milk powders with the relative standard deviations（RSD） over 2.4%～3.1% and the recovery over 98.2%～103.2%.

关 键 词：动力学光度法 阻抑作用 锌(II) 偶氮胂I 过氧化氢 

分 类 号：O657.31[理学—分析化学]