[Hg(SCN)4]2-对蛋白质的荧光猝灭反应及其分析应用

在pH=1.4~3.4的酸性介质中, Hg(SCN)4]2-配阴离子可与牛血清白蛋白(BSA)、 γ-球蛋白(γ-G)和血红蛋白(Hb)等蛋白质反应形成复合物, 从而引起蛋白质荧光的猝灭. 荧光猝灭的程度在一定范围内与Hg(Ⅱ)的浓度呈线性关系, 可用于Hg(Ⅱ)的测定. 该方法有较高的灵敏度, 检出限(3σ)分别为4.4 ng/mL(BSA)、 6.5 ng/mL(γ-G)和12.9 ng/mL(Hb), 其中以BSA体系灵敏度最高. 研究了Hg(SCN)4]2-与蛋白质相互作用对荧光光谱的影响、 适宜的反应条件和影响因素; 结合吸收光谱的变化、 温度的影响以及某些热力学参数讨论了荧光猝灭反应的机理; 并以Hg(SCN)4]2--BSA体系为例考察了共存物质的影响. 结果表明, 该方法具有良好的选择性. 以BSA为探针采用荧光猝灭法测定了红药水中汞溴红和乙肝疫苗中硫柳汞的含量, 结果令人满意.

Proteins Fluorescence Quenching by [ Hg (SCN) 4 ] 2- and Its Analytical Application

Hg(SCN)4]2-in acidic medium of pH=1.4—3.4 could react with proteins,including bovine serum albumin(BSA),γ-globin(γ-G) and hemoglobin(Hb),to form complexes.As a result,the fluorescence intensities of the proteins were significantly quenched.The quenched fluorescence intensities(ΔF) in a certain range were linearly related to the concentration of Hg(Ⅱ),and the detection limit(3σ) were 4.4 ng/mL(BSA),6.5 ng/mL(γ-G) and 12.9 ng/mL(Hb),respectively.The effects of the interaction on the fluorescence spectral characteristics of these complexes,suitable reaction conditions and influencing factors were investigated.The quenching mechanism was studied by absorption spectroscopy,binding constant and corresponding thermodynamic parameters at different temperatures.Some potential interferents on the assay by BSA were investigated.The method displayed good selectivity and was satisfactorily applied to the determination of asceptichrome in mercurochrome solution and thiomersalatum in HB-vaccine.