响应范围可调的pH荧光传感器的构建及其性能研究

合成并表征了化合物N,N'-二谷氨酸铵盐-3,4,9,10-苝四羧酸二酰亚胺(PTCDG).此化合物水溶性好,荧光量子产率高.基于此,设计了一组新颖的响应范围可调的pH荧光传感器.PTCDG与顺磁性的Fe3+可按1∶1络合,络合常数为6.5×105,考察了其它金属离子的影响,表明PTCDG对Fe3+有良好的选择性.PTCDG与Fe3+结合后,由于PET效应,荧光猝灭,伴随pH值增大,Fe3+与OH-形成Fe(OH)3,从体系中沉淀出来,荧光团被释放,从而荧光恢复.在不同的Fe3+的良好配体存在条件下,形成Fe(OH)3的pH范围向碱性方向移动.PTCDG,PTCDG/Fe3+,PTCDG/Fe3+/三乙胺,PTCDG/Fe3+/吡啶、PTCDG/Fe3+/邻菲罗啉的响应范围分别为4.0～6.0,5.0～10,5.0～7.0,6.0～8.0和7.0～9.0,涵盖了pH值4.0～10的区间,实现了响应范围的可调.考察了内在的干扰物对该传感器的效能的影响,探讨了此体系的荧光传感机理.此传感器具有很多优异的性能,响应的范围可调且近中性,荧光和颜色变化明显,响应快,具有较高的灵敏性.

Synthesis and Characterization of a pH Fluorescence Sensor with Tunable Response Range

N,N′-bi(L-glutamic amine)-perylene-3,4;9,10-dicarboxylic diimide(PTCDG)was synthesized and characterized.The compound abovementioned was water-soluble and had high fluorescent quantum yield.A set of novel fluorescent pH sensors with tunable response range were designed based on the PTCDG,which could react with paramagnetic Fe3+ to form a 1:1 complex.The association constant was 6.5×105.The effects of foreign ions were examined and it was shown that PTCDG has a good selectivity to Fe3+.The PTCDG could coordinate the paramagnetic Fe3+ ions to switch off itself by PET quenching and could release Fe3+ to turn on the fluorescence again by forming Fe(OH)3 as the pH increase.Moreover,under the conditions of different good ligands for Fe3+,the formation of Fe(OH)3 moves to the alkaline pH range direction.The tunable response pH range covers 4.0-10.0(4.0-6.0 for PTCDG,5.0-10.0 for PTCDG/Fe3+,5.0-7.0 for PTCDG/Fe3+/triethylamine,6.0-8.0 for PTCDG/Fe3+/pyridine,7.0-9.0 for PTCDG/Fe3+/phenanthroline).The effects of the internal interference were investigated and the pH sensing mechanism was also discussed.The pH sensor had many excellent properties,such as tunable response range including the nearly neutral environment,obvious change of fluorescence and color,fast response and high sensi-tivity.