镉(Ⅱ)的共振散射光谱研究及应用

Resonance Scattering Spectrum of Cadmium(Ⅱ) and Its Application

由于镉在环境中具有高毒性和生物蓄积性,对人体和环境会产生巨大的危害,因而测定其在环境中的浓度是十分必要的。本研究基于镉(Ⅱ)-蛋白质-刚果红体系的共振瑞利散射和共振非线性散射光谱建立了测定环境水样中微量镉(Ⅱ)的新方法。在p H=4的BR缓冲溶液中,镉(Ⅱ)与牛血清白蛋白溶液及刚果红溶液反应生成三元离子缔合络合物,使该体系中的共振瑞利散射(RRS)、二级散射(SOS)和倍频散射(FDS)信号明显增强,其最大散射波长分别位于波长560 nm(RRS)、690 nm(SOS)和352 nm(FDS)处。在优化的实验条件下,ΔI与镉(Ⅱ)浓度在一定范围内呈现良好的线性关系,检出限分别为0. 31μg/L(RRS)、0. 29μg/L(SOS)、0. 34μg/L(FDS)。将该方法用于实验室废水、涪江河水和农夫山泉中镉(II)的测定,水样中镉(Ⅱ)的回收率在93. 2%～107. 7%之间,相对标准偏差在0. 8%～3. 1%之间,取得了较理想的结果。

Due to the high toxicity and bioaccumulation of cadmium in organisms and environment,it will cause great harm to the human body and the environment.Therefore,it is necessary to determine the concentration of cadmium in the natural environment.In this study,a new method for the determination of trace cadmium(Ⅱ)in environmental water samples was established based on the resonance Rayleigh scattering and resonance nonlinear scattering of the cadmium(Ⅱ)-protein-congo red system.In pH=4 BR buffer solution,cadmium(Ⅱ)reacts with bovine serum albumin solution and congo red solution to form a ternary ion-associated complex,which can greatly enhance the resonance Rayleigh scattering(RRS),second-order scattering(SOS)and frequency doubling scattering(FDS)signals of the system.The maximum scattering wavelength locates at 560 nm(RRS),690 nm(SOS)and 352 nm(FDS),respectively.Under the optimum conditions,enhanced peak signal(ΔI)has good linearity with the concentration of cadmium(Ⅱ)within a certain range.The detection limits are 0.31μg/L(RRS),0.29μg/L(SOS)and 0.34μg/L(FDS)respectively.The method is applied to the determination of cadmium(Ⅱ)in laboratory wastewater,Fujiang River water and Nongfu Spring with recovery rates between 93.2%and 107.7%,and the relative standard deviations(RSD)are 0.8%-3.1%.The results are satisfactory.