胶束增敏荧光法测定锆

在CTAB胶束介质中配合物组成可发生一系列变化,这是其对吸光度及荧光增敏的决定因素。在合适的CTAB浓度下,可形成Zr(Ⅳ):Morin=1:3的高次配合物,使体系的摩尔吸光系数增加3倍多;但随着CTAB浓度的增大,形成了Zr(Ⅳ):Morin:SO₄^2-=1:1:2的混配配合物,硫酸根起了辅助配体的作用,荧光强度增强数十倍,稳定性也有很大提高,对CTAB胶束改变配合物组成及增敏荧光的原因进行了研究。据此建立了胶束增敏荧光测定锆的新方法。该法的检测下限为0.2ng/mL,线性范围为0.2ng/mL～0.5μg/mL,选择性、稳定性均好。

Micelle-Sensitized Fluorometric Determination of Zirconium and Its Application

The effect of surfactants on the fluorescence of the zirconium-morin system was described In 0.12 mol/L H₂SO₄ solution,the fluorescent intensity of this complex can be enhanced by cationic surfactant,cetyltrimethylammonium bromide(CTAB),but no effect in HCl medium.It was found that the mechanism of the effects of CTABon the absorbance and fluorescence were different.The absorptiometric measurement was favored with the formation of 1:3(Zr(Ⅳ):morin) complex in the proper CTABconcentration(near the critical micelle concentration,cmc,of CTAB).With the CTABconcentration increasing,a mixed-ligand complex was formed,and the intensity of fluorescence was enhanced dramatically.The role of CTABin the formation of the mixed-ligand complex and the enhancement of fluorescence was discussd.Anew analytical method for the fluorometric determination of Zr(Ⅳ)was described also.The detection limits of the method is 0.2ng/mL,calculated with S/N=6.The linear range of the calibration graph was 0.2ng/mL～0.5μg/mL.The intensity of fluorescence is stable for at least 24 hours.From the study of interfering ions,it was deduced that the selectivity of the method is high,This is one of the.best system for determination of traces of zirconium.