Zhang Ying, Yang Ronghua, Liu Feng, Li Ke'an
College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Anal Chem. 2004 Dec 15;76(24):7336-45. doi: 10.1021/ac049477+.
A new zinc(II) porphyrin conjugate with an appended pyrene subunit has been synthesized and shown to exhibit significant and analytical usefulness for fluorescence sensing toward imidazole derivatives. The molecular recognition was based on the bridging interaction of the imidazole ring of analyte with the zinc(II) center of the porphyrin, while the transduction signal for the recognition process was the pyrene excimer fluorescence. The sensor was constructed and applied for fluorescence assay of histidine in aqueous solution by immobilizing the sensing material in a plasticized PVC membrane. When the membrane was bathed in an alkaline solution void of histidine, zinc(II) porphyrin was present in the monomer form, and pyrene emitted monomer fluorescence at 378 and 397 nm. With the presence of histidine in the sample solution, histidine was extracted into the membrane phase and bridged with the Zn(II) center of the porphyrin, causing the monomer porphyrin to be converted to its dimeric species. Since the formation of porphyrin dimer was accompanied by the enhancement of pyrene excimer emission at 454 nm, the chemical recognition process could be directly translated into a fluorescent signal. With the optode membrane M1 described, histidine in sample solution from 6.76 x 10(-7) to 5.01 x 10(-3) M can be determined. The limit of detection was 1.34 x 10(-7) M. The optical selectivity coefficient obtained for histidine over biologically relevant amino acids and anions met the selectivity requirements for the determination of histidine in biological samples. Serum histidine values obtained by the optode membrane fell in the normal range of the content reported in the literature and were in good agreement with those obtained by HPLC.
一种带有芘亚基的新型锌（II）卟啉共轭物已被合成，并显示出对咪唑衍生物进行荧光传感具有显著的分析实用性。分子识别基于分析物咪唑环与卟啉锌（II）中心的桥连相互作用，而识别过程的转导信号是芘激基缔合物荧光。通过将传感材料固定在增塑PVC膜中构建了该传感器，并将其应用于水溶液中组氨酸的荧光测定。当膜浸泡在不含组氨酸的碱性溶液中时，锌（II）卟啉以单体形式存在，芘在378和397nm处发射单体荧光。当样品溶液中存在组氨酸时，组氨酸被萃取到膜相中并与卟啉的Zn（II）中心桥连，导致单体卟啉转化为其二聚体形式。由于卟啉二聚体的形成伴随着454nm处芘激基缔合物发射的增强，化学识别过程可以直接转化为荧光信号。使用所述的光极膜M1，可以测定样品溶液中浓度范围为6.76×10^(-7)至5.01×10^(-3)M的组氨酸。检测限为1.34×10^(-7)M。获得的组氨酸相对于生物相关氨基酸和阴离子的光学选择性系数满足生物样品中组氨酸测定的选择性要求。通过光极膜获得的血清组氨酸值落在文献报道的正常含量范围内，并且与通过高效液相色谱法获得的值高度一致。
