Yang Ronghua, Wang Kemin, Long Liping, Xiao Dan, Yang Xiaohai, Tan Weihong
College of Chemistry and Chemical Engineering, State Key Lab of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, China.
Anal Chem. 2002 Mar 1;74(5):1088-96. doi: 10.1021/ac010386b.
A plasticized polymer film, poly(vinyl chloride) (PVC) incorporated with a specific porphyrin dimer, is shown to exhibit significant and analytical usefulness for optical response toward histidine. The porphyrin dimer containing a free-base porphyrin and a covalently linked metalloporphyrin is shown to be weakly fluorescent as a result of the photoinduced intramolecular electron transfer from the inner free-base porphyrin in singlet excited state to a low-spin cobalt(II). The fluorescence enhancement of the membrane by histidine is based on favorable extraction of histidine into the bulk organic membrane and complexation with the inner metallopophyrin moiety and inhibiting the electron transfer process. With the optode membrane described, histidine in a sample solution from 0.0045 to 1.53 mM can be determined. The calibration curve of the optode membrane for histidine shows a good correlation with the mathematically derived formalism and, thus, confirms the theoretically expected behavior. The sensor presented exhibits high selectivity toward histidine over several amino acids and common inorganic anions. The optical selectivity coefficients obtained for histidine over other biologically relevant amino acids and anions are shown to meet the selectivity requirements for the monitoring concentration levels of histidine in biological samples. The selective characteristic of the sensor has been discussed in the view of the coordination chemistry of metalloporphyrin.
一种增塑聚合物薄膜，即掺入特定卟啉二聚体的聚氯乙烯（PVC），已被证明对组氨酸具有显著的光学响应且具有分析实用性。含有游离碱卟啉和共价连接的金属卟啉的卟啉二聚体，由于单重激发态下从内部游离碱卟啉到低自旋钴（II）的光致分子内电子转移，显示出弱荧光。组氨酸使膜的荧光增强，这是基于组氨酸被有利地萃取到本体有机膜中，并与内部金属卟啉部分络合，从而抑制了电子转移过程。使用所述的光极膜，可以测定样品溶液中0.0045至1.53 mM的组氨酸。光极膜对组氨酸的校准曲线与数学推导的形式具有良好的相关性，因此证实了理论预期的行为。所展示的传感器对组氨酸的选择性高于几种氨基酸和常见无机阴离子。组氨酸相对于其他生物相关氨基酸和阴离子获得的光学选择性系数表明，满足生物样品中组氨酸监测浓度水平的选择性要求。已从金属卟啉的配位化学角度讨论了传感器的选择性特性。
