增强型四苯基咪唑类荧光探针及其对硫醇的识别性能

A TURN-ON FLUORESCENCE PROBE BASED ON TETRAPHENYL IMIDAZOLE AND ITS RECOGNITION STUDY FOR THIOL

以2-(1,4,5-三苯基-1H-咪唑-2-)苯酚和2,4-二硝基氟苯为原料,合成了增强型的探针2-[2-(2,5-二硝基苯氧基)苯基]-1,4,5-三苯基-1H-咪唑(DNP-TPI),对其结构进行了表征,研究了探针DNP-TPI通过硫解反应对H2S和硫醇的识别性质。在体积比为2∶8的MeOH和HEPES的缓冲溶液中(pH=7.4,c(CTAB)=4.0mmol/L),探针DNP-TPI与HS^-、L-Cys、GSH和Hcy均能发生硫解反应,通过荧光增强效果实现对硫醇的识别。对L-Cys识别情况的研究表明,探针DNP-TPI对L-Cys具有良好的识别选择性和灵敏度,不受其它常见阴离子的干扰,硫解反应符合线性关系,反应的速率常数为0.0203min^-1,检测限为7.9×10^-5mol/L。此外,探针DNP-TPI在较大的pH范围内对L-Cys实现良好的荧光响应,应用范围较广。

A new turn-on fluorescence probe 2-(2-(2,5-dinitrophenoxy)phenyl)-1,4,5-triphenyl- 1 H -imidazole (DNP-TPI) was synthesized from 2-(1,4,5-triphenyl-1 H -imidazol-2-yl)phenol and 1-fluoro-2,4-dinitrobenzene,and the structure of probe DNP-TPI was characterized. The recognized behaviors of probe DNP-TPI to H 2S and thiol were investigated by the reaction of thiolysis. Under the conditions of MeOH and HEPES (pH=7.4, c (CTAB)=4.0 mmol/L),the turn-on effects of fluorescence intensity were realized by the thiolysis of the probe DNP-TPI to H 2S,L-Cys,GSH and Hcy. For example of L-Cys,probe DNP-TPI exhibited good selectivity and sensitivity without interfering form other common anions. Meanwhile,the fluorescence intensity was linear function with the concentration of L-Cys with k value of 0.020 3 min^-1 and the detection limit was calculated to be 7.9×10^-5 mol/L. Furthermore,probe DNP-TPI showed good fluorescence response to L-Cys in a broad pH range indicating its extensive application.