基于酪氨酸荧光猝灭的荧光光度法测定水样和奶粉中痕量铁  

Fluorospectrophotometric Determination of Traces of Iron in Milk Powder and Water Sample by Quenching of Fluorescence of Tyrosine

作　　者：马红燕[1] 孙雪花[1] 田锐[1] 宋诗稳[1] 

机构地区：[1]延安大学化学与化工学院,延安716000

出　　处：《理化检验（化学分册）》2009年第5期575-577,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：陕西省教育厅专项科研基金资助课题(04JK305)

摘　　要：研究了铁（Ⅲ）对酪氨酸荧光信号的猝灭作用。试验发现：在pH4．46的乙酸-硼酸-磷酸-氢氧化钠缓冲溶液中，铁（Ⅲ）能与酪氨酸形成络合物，而猝灭酪氨酸分子的内源性荧光，使其荧光强度显著降低。据此，提出酪氨酸-铁（Ⅲ）体系测定铁（Ⅲ）的荧光分析方法。体系的最大激发波长与最大发射波长分剐位于277nm与306nm。铁（Ⅲ）的浓度在1．6×10^-8～3．2×10^-5mol·L^-1范围内与荧光猝灭值△F成正比，方法的检出限（3sb／k）为1．2×10^-8mol·L^-1。直接用于水样和奶粉中微量铁（Ⅲ）的测定，所得结果与邻菲哆啉光度法所测得的结果相符。以此两种样品作基体加入铁（Ⅲ）标准溶液进行了回收试验，测得回收率在98．2％～99．9％之间，测定值的相对标准偏差（n=5）均小于3％。In an acetate-borate-phosphate buffer medium of pH 4.46, a complex was formed by the reaction between Fe（ Ⅲ） and tyrosine, leading to quenching of inherent fluorescence of tyrosine Linear relationship between the magnitude of decrease in fluorescence intensity （△F） and concentration of Fe（ Ⅲ） was obtained in the range of 1.6X10-8--3.2X 10^-5mol ·L^-1 when measured at the wavelengths of 277 nm （λex） and 306 nm （λex）. Contents of iron in a water sample and a sample of milk powder were determined by the proposed method, giving results in consistency with those obtained by the a-phenanthroline photometric method. Using these samples as matrixes, test for recovery was made by standard addition method, values of recovery obtained were in the range of 98. 2% - 99. 9%, with values of RSD＇s （n=5） less than 3%. Detection limit （3Sb/k） of the method was found to be 1.2×10^-8mol· L^-1

关 键 词：荧光猝灭法 酪氨酸 铁(Ⅲ) 奶粉 水样 

分 类 号：O657.31[理学—分析化学]