痕量镉的催化动力学荧光分析法

The Determination of Trace Amounts of Cadmium by Catalytic Kinetic Fluorometry

Guilbault等曾捉及利用Cd(Ⅱ)对酶催化非荧光物质高香草酸氧化为强荧光化合物反应的抑制作用可测定镉,但迄今尚未见利用催化动力学荧光分析法测定痕量镉的报道,本文拟利用Cd(Ⅱ)和咪唑对Co(Ⅲ)-T(4-SP)P络合物生成反应的催化作用[2],建立痕量镉的催化动力学荧光分析法。

A new method of catalytic kinetic fluorometry has been established for the determination of trace amounts of cadmium.It is based on the catalysis of both Cd(Ⅱ)and imidazolc on the reaction of complex formation between Co(Ⅲ)and α,β,γ,δ-tetrakis(4-sulphophcnyl)porphine[T(4-SP)P]in H_(3)BO_(3)-Na_(2)B_(4)O_(7) buffer solution with pH8.5.Fixed time method is used in measuring the reaction rate.The concentration of the product,Co(Ⅲ)-T(4-SP)Pcomplex,is monitored by measuring the flourescence intensity of T(4-SP)Pwhich is decreased as the concentration of the product increases.The calibration graph is rectilinear over the concentration range of 0-16 ng Cd(Ⅱ)/ml.The limit of detection is 0.5 ng Cd(Ⅱ)/ml,the accuracy of determination,±6%.Eight replicate determinations of solutions containing 0.2μg Cd(Ⅱ) show a relative standard deviation of 4.3%.