识别酪胺的咔唑类荧光探针合成与应用

Synthesis and application of a carbazole-based fluorescent probe for recognizing tyramine

目的:基于激发态分子内质子转移(ESIPT)机制,研发一种用于酪胺检测的新型小分子荧光探针CPIM。方法:通过4-(9H-咔唑-9-基)苯胺和3,5-二碘水杨醛反应缩合得到咔唑类小分子荧光探针CPIM,采用核磁共振氢谱、红外光谱、高分辨质谱表征其结构。通过紫外光谱和荧光光谱等方法研究荧光探针对酪胺的检测性能。通过Job's曲线、红外光谱和核磁共振氢谱对检测机制进行研究。采用标准加入法验证荧光探针的实际应用性。结果:在365 nm紫外灯下,CPIM可以实现酪胺分子的可视化检测。CPIM对酪胺识别具有良好的选择性、灵敏性、抗干扰性、稳定性和重现性,在0~5.0×10^(-6)mol/L浓度范围内,体系荧光强度与酪胺浓度呈良好的线性关系,其检测限为4.36×10^(-7)mol/L,与酪胺的结合常数为9.98×10^(4)M^(-1)。CPIM与酪胺以1:1结合脱水后形成复合物,进而抑制ESIPT过程,并生成大的p-π共轭体系导致荧光显著增强。此外,CPIM还可对实际样品中的酪胺进行检测。结论:CPIM具有良好的酪胺检测能力,具有选择性高、灵敏性好、检测限低、稳定性好的特点。

Objective:To develop a turn-on small molecule fluorescent probe CPIM for tyramine detection based on the excited state intramolecular transfer(ESIPT)mechanism.Methods:The carbazole small molecule fluorescent probe CPIM was obtained by the reac-tion and condensation of 4-(9H-carbazol-9-yl)aniline and 3,5-diiodosalicylaldehyde,and the structure of CPIM was characterized by 1H nuclear magnetic resonance spectrometry(1H NMR),infrared spectroscopy(IR),and high resolution mass spectrometry(HR-MS).The performance of CPIM in detecting tyramine was studied by UV spectrum,fluorescence spectroscopy and other methods.The detec-tion mechanism was investigated by Job's plot,IR,and 1H NMR.The practical applicability of fluorescent probe was verified by the standard addition method.Results:The visual detection of CPIM for tyramine can be realized under 365 nm UV chamber.CPIM has good selectivity,sensitivity,anti-inference,stability and repeatability for the recognition of tyramine.There was a good linear relation-ship between the fluorescence intensity of probe CPIM and the concentration of tyramine in a range of 0 to 5.0×10^(-6)mol/L,with the de-tection limit of 4.36×10^(-7) mol/L.The binding constant of tyramine with CPIM was 9.98×10^(4) M^(-1).CPIM binds to tyramine in a 1:1 ratio and dehydrates to form a complex,which in turn inhibits the ESIPT process and generates a large p-πconjugation system leading to a significant enhancement of fluorescence.Besides,CPIM can be used for the detection of real samples.Conclusion:CPIM has good tyra-mine detection ability with high selectivity,good sensitivity,low detection limit and good stability.