对称性中位取代羟基卟啉荧光检测水体痕量汞离子研究

Study on fluorescence detection of trace mercury ions in water by symmetric di-and tetra-substituted hydroxyporphyrins

利用两种具有对称性结构的羟基中位取代卟啉meso-5,15-二-(4-羟基苯基)10,20-二苯基卟啉(P_(2OH))和meso-5,10,15,20-四-(4-羟基苯基)卟啉(P_(4OH))作为荧光探针,检测水体中痕量汞离子。比较两种探针对汞离子的选择性、检测灵敏性及对时间和pH的稳定性。并对其检测机理进行初步讨论,总结两种对称性羟基卟啉与水体Hg^(2+)的相互作用规律。结果显示,两种对称性羟基卟啉在其他金属离子存在条件下对汞离子显示荧光强度变化和显色反应,其浓度变化显示两种卟啉都呈现荧光比率探针的变化规律,荧光比率与水体中汞离子的浓度呈线性关系,相关系数均大于0.99。在不同的pH值变化范围和10 min内,两种对称性探针分子的荧光发射峰和荧光比率值均保持稳定。P_(4OH)的检测灵敏性和稳定性较强,这主要是因为中位羟基数目的对称性增加,可增强其分子中中位羟基与Hg^(2+)的相互结合作用,从而引起荧光光谱变化。

Using two symmetrical hydroxyl porphyrins:meso-5,15-bis-(4-hydroxyphenyl)10,20-diphenylporphyrin(P_(2OH_)and meso-5,10,15,20-tetra-(4-hydroxyphenyl)phenylporphyrin(P_(4OH))as ratio fluorescent probes to detect trace Hg^(2+) in water.The selectivity,sensitivity,time and pH stability of two hydroxyl porphyrins were compared and the fluorescence detection mechanism was preliminarily discussed.At the same time,by the preliminary discussion of detection mechanism,the interactions between two symmetric hydroxyporphyrins and Hg^(2+)were summarized.The results indicated that both P_(4OH) and P_(2OH) could selectively detect trace Hg^(2+)in water,whose fitting curve were linearly correlated,and the correlation coefficients were greater than 0.99.Two symmetrical hydroxyporphyrins exhibited stable to 10 mins and pH.Compared with P_(2OH),P_(4OH) is more stable,due to the increasing symmetry of four meso-hydroxyl groups substituted porphyrin,which can enhance the combination between peripheral hydroxyl groups and Hg^(2+),promoting the sensitivity and the stability of fluorescent detection.