基于稀土铕离子配合物的时间分辨荧光pH探针的合成及应用

The Synthesis and Application of Time-Resolved Fluorescence pH Probe Based on Rare Earth Europium Ion Complex

以4，7-二苯基-1，10-菲哆啉（母体）和2-噻吩甲酰三氟丙酮为协同剂和β-二酮配体，合成了一种稀土三元铕离子配合物，其荧光寿命为0．5440ms，并以其为荧光探针对水环境的pH进行时间分辨荧光测定。荧光探针的时间分辨荧光强度在pH7．00～8．95时达到最大值并保持较好的稳定性；在pH小于7．00和pH大于8．95时，荧光探针的时间分辨荧光强度随着pH变化而变化；在pH2．50～7．00和pH9．91-14．00时，荧光探针的时间分辨荧光猝灭率与pH呈线性关系。溶解氧浓度和离子强度变化对pH测定结果无影响。采用荧光探针测定实际水样的pH，结果与玻璃电极的测定结果相符，测定值的相对标准偏差（n=8）在4．3％～8．1％之间。

A rare earth ternary europium ion complex with fluorescent lifetime of 0. 544 0 ms was synthesized by using 4,7-diphenyl-1,10-phenanthroline and 2-thenoyltrifluoroacetone as synergic agents and β-diketone ligands. The complex was used as fluorescent probe for pH determination of environmental water samples by time-resolved fluorescence analysis. The fluorescent probe showed the maximum and stable time-resolved fluorescence intensity when the pH ranged from 7. 00 to 8. 95, while the time-resolved fluorescence intensity changed obviously in acidic （pH〈 7. 00） and strong alkaline （pH〉8. 95） conditions. The time-resolved fluorescence quenching of the fluorescent probe showed linear response toward pH in the range of 2. 50- 7. 00 or 9. 91 - 14. 00. The prepared fluorescent probe was insensitive to dissolved oxygen and ionic strength. The prepared fluorescent probe was used to determine pH of real water samples, giving results in consistent with those obtained by glass electrode and RSDs （n=8） in the range of 4. 30%-8. 1%.