Zhu Xiaojing, Wang Xiaolei, Jiang Chongqiu
Department of Chemistry, Shandong Normal University, Jinan, Shandong 250014, China.
Anal Biochem. 2005 Jun 15;341(2):299-307. doi: 10.1016/j.ab.2005.03.014.
A new spectrofluorimetric method was developed for the determination of trace amounts of heparin (Hep). Using tetracycline (TC)-europium ion (Eu3+) as a fluorescent probe, in the buffer solution at pH 8.8, Hep can remarkably enhance the fluorescence intensity of the TC-Eu3+ complex at lambda=612 nm and the enhanced fluorescence intensity of Eu3+ is in proportion to the concentration of Hep. Optimal conditions for the determination of Hep were also investigated. The linear range and detection limit for the determination of Hep were 0.02 to 1.6 microg/ml and 4.45 ng/ml, respectively. This method is simple, practical, and relatively free of interference from coexisting substances, and it can be applied successfully to assess Hep in biological samples. By the Rosenthal graphic method, the association constant and binding numbers of Hep with the probe were 4.46 x 10(4) L/mol and 16.2, respectively. Moreover, the enhancement mechanism of the fluorescence intensity in the TC-Eu3+ system, the TC-Eu(3+)-Hep system, and the TC-Eu(3+)-Hep-CTMAB system is also discussed.
开发了一种新的荧光分光光度法用于测定痕量肝素（Hep）。以四环素（TC）-铕离子（Eu3+）作为荧光探针，在pH 8.8的缓冲溶液中，肝素能显著增强TC-Eu3+络合物在λ=612 nm处的荧光强度，且Eu3+增强的荧光强度与肝素浓度成正比。还研究了测定肝素的最佳条件。测定肝素的线性范围和检测限分别为0.02至1.6μg/ml和4.45 ng/ml。该方法简单、实用，相对不受共存物质的干扰，可成功应用于生物样品中肝素的评估。通过罗森塔尔图解法，肝素与探针的缔合常数和结合数分别为4.46×10(4) L/mol和16.2。此外，还讨论了TC-Eu3+体系、TC-Eu(3+)-Hep体系和TC-Eu(3+)-Hep-CTMAB体系中荧光强度的增强机制。
