四碘荧光素钠-邻啡啰啉荧光光谱法测定水中镉

Determination of Cadmium in the Water by Fluorometry with Tetraiodofluorescein Sodium Salt and 1,10-phenantroline

目的建立一种荧光光谱测定水中镉的新方法。方法在pH=6.0的乙酸-乙酸钠(HAc-NaAc)缓冲介质中,镉(Cd2+)与四碘荧光素钠、邻啡啰啉反应形成络合物,体系的最大激发波长为525nm,发射波长为531 nm,在一定范围内,其荧光强度与Cd2+的浓度成线性关系。结果 Cd2+浓度在3.92×10-6mol/L^2.00×10-5mol/L范围内,荧光强度变化值(ΔF)与镉离子浓度(cCd2+)有良好的线性关系,线性方程为ΔF=58.9c(×10-5mol/L)+4.8,相关系数r=0.999 2,检出限为1.91×10-6mol/L,样品加标回收率为86.6%~101.5%。结论本方法可直接用于水中镉的测定,选择性好,准确可靠,结果满意。

Objective To establish a new method of fluorescence spectroscopy to determine trace cadmium in water. Methods At pH = 6.0 HAc-NaAc buffer medium, the complex with Cd2＋ , Tetraiodofluorescein sodium salt and 1,10- Phenanthroline hydrate was formed. The results showed that with maximum wavelength for 525 nm and the emission wavelength for 531 nm there was a good linear relationship between the fluorescence intensity and the concentration of Cd2＋. Results Among the range of 3.92 × 10^- 6 mol/L -2.00 ×10^-5 mol/L,the linear equation was AF = 58.9c（× 10^-5 mol/L） ＋4.8 ,and the correlation coefficient was 0.9992. The average recoveries were between 86.6% and 101.5%. The method detection limit was 1.91 × 10^- 6 mol/L. Conclusion The proposed method is sensitive, selective and simple, and has been used success- fully in the determination of cadmium in water samples,which has a good satisfactory results.