以罗丹明B、乙二胺和乙二醛为反应原料, 合成了一种新型的荧光增强型识别Fe3+的分子探针(fluorescent probe, FP)。用核磁和质谱对其分子结构进行了表征, 并通过荧光光谱研究了FP对Al3+、Pb2+、Cu2+、Cd2+、Mn2+、Hg2+、Mg2+、Ca2+、K+、Na+等不同金属离子的识别性能。研究结果表明: 在纯甲醇溶剂中, 探针FP对Fe3+的识别具有较好的选择性, 且基本不受其他金属离子的干扰; 通过Jobs曲线可知, 探针FP与Fe3+的络合比为1∶3; Fe3+浓度在4×10-4~5×10-3 mol/L范围内时, 探针FP的荧光强度与Fe3+浓度具有良好的线性关系, 线性相关系数为0.995 3。

A novel fluorescent probe (FP) for detecting Fe3+ was synthesized from rhodamine B, ethylenediamine and glyoxal. Its molecule structure of FP was characterized by 1H NMR and MS, and its fluorescent properties of FP in detecting Fe3+ and other different metal ions were investigated by fluorescent spectroscopy. The experimental results show that FP has a higher selective recognition for Fe3+ in CH3OH, and other metal ions, such as Al3+, Pb2+, Cu2+, Cd2+, Mn2+, Hg2+, Mg2+, Ca2+, K+ and Na+, have no effects on its recognition for Fe3+. The complexation ratio of FP/Fe3+ is l∶3 from the method of Jobs plot by UV-Vis spectroscopy. When the concentration of Fe3+ is 4×10-4~5×10-3 mol/L, there is a good linear relationship between the fluorescence intensity of FP and the concentration of Fe3+, and the linear correlation coefficient is 0.995 3. The analysis reveals that FP can be used as a fluorescent sensor for the selective detection of Fe3+.