Li Fang, Sun Xiang-ying
College of Material Science and Engineering, Huaqiao University, Quanzhou 362021, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2008 Sep;28(9):2165-8.
The fluorescence spectra of the succinic acid (7-hydroxy-coumarin) ester (SCE) of different concentration in water and ethanol solvents were studied. It was found that the peak wavelength changes not only with solvent, but also with the concentration. These phenomena of spectra have been discussed on the basis of solvent properties and dimerisation of SCE in hydrogen bonding solvents. The author thought that there are dimerisation phenomena in the SCE solutions at high concentration. The formation of dimer was caused by the aid of hydrogen bonding between SCE and solvent or between SCE themselves. Its acidic dissociation constant at excited state was determined based on the changes of the fluorescence spectra in water. And a simple and sensitive fluorescence quenching method for the determination of trace iron was developed. The method is based on the reaction of SCE with iron in hydrochloric acid medium. The fluorescence intensity was measured with excitation and emission wavelengths of 347 and 457 nm, respectively. The linear range for the determination of iron was 0.66-6.59 microg x L(-1). The detection limit was 51 ng x L(-1). The author contrasted SCE with 7-hydroxy-coumarin to determine Fe3+, and found the sensitivity of SCE is 10(4) higher than that of 7-hydroxy-coumarin. To our thinking there is a carboylate group in SCE, whose coordinate force with iron is stronger than hydroxide radical in 7-hydroxy-coumarin.
研究了不同浓度的琥珀酸（7-羟基香豆素）酯（SCE）在水和乙醇溶剂中的荧光光谱。发现其峰值波长不仅随溶剂变化，还随浓度变化。基于溶剂性质以及SCE在氢键溶剂中的二聚作用，对这些光谱现象进行了讨论。作者认为在高浓度的SCE溶液中存在二聚现象。二聚体的形成是借助SCE与溶剂之间或SCE自身之间的氢键作用。基于其在水中荧光光谱的变化测定了其激发态酸性解离常数。并且建立了一种简单灵敏的荧光猝灭法测定痕量铁。该方法基于SCE与铁在盐酸介质中的反应。分别以347和457 nm为激发波长和发射波长测量荧光强度。铁的测定线性范围为0.66 - 6.59 μg·L⁻¹。检测限为51 ng·L⁻¹。作者将SCE与7-羟基香豆素对比测定Fe³⁺，发现SCE的灵敏度比7-羟基香豆素高10⁴倍。我们认为SCE中存在一个羧酸盐基团，其与铁的配位力比7-羟基香豆素中的羟基更强。
