Centro de Lasers e Aplicações, IPEN/CNEN-SP, Brazil.
Anal Biochem. 2010 May 1;400(1):19-24. doi: 10.1016/j.ab.2010.01.030. Epub 2010 Feb 1.
Low-density lipoprotein (LDL) particles are the major cholesterol-carrying lipoprotein in the human circulation from the liver to peripheral tissues. High levels of LDL-Cholesterol (LDL-C) are known risk factor for the development of coronary artery disease (CAD). The most common approach to determine the LDL-C in the clinical laboratory involves the Friedewald formula. However, in certain situations, this approach is inadequate. In this paper we report on the enhancement on the Europium emission band of Europium chlortetracycline complex (CTEu) in the presence of LDL. The emission intensity at 615 nm of the CTEu increases with increasing amounts of LDL. This phenomenon allowed us to propose a method to determine the LDL concentration in a sample composed by an aqueous solution of LDL. With this result we obtained LDL calibration curve, LOD (limit of detection) of 0.49 mg/mL and SD (standard deviation) of 0.003. We observed that CTEu complex provides a wider dynamic concentration-range for LDL determination than that from Eu-tetracycline previously. The averaged emission lifetimes of the CTEu and CTEu with LDL (1.5 mg/mL) complexes were measured as 15 and 46 micros, respectively. Study with some metallic interferents is presented.
低密度脂蛋白（LDL）颗粒是人类循环中从肝脏到外周组织的主要胆固醇携带脂蛋白。高水平的 LDL-胆固醇（LDL-C）是冠心病（CAD）发展的已知危险因素。临床实验室中测定 LDL-C 的最常用方法涉及 Friedewald 公式。然而，在某些情况下，这种方法是不够的。在本文中，我们报告了 LDL 存在下 Eu 氯四环素配合物（CTEu）的 Eu 发射带的增强。CTEu 在 615nm 处的发射强度随 LDL 量的增加而增加。这种现象使我们能够提出一种方法来确定由 LDL 的水溶液组成的样品中的 LDL 浓度。根据这一结果，我们得到了 LDL 校准曲线，检测限（LOD）为 0.49mg/mL，标准偏差（SD）为 0.003。我们观察到 CTEu 配合物为 LDL 测定提供了比以前的 Eu-四环素更宽的动态浓度范围。CTEu 和 CTEu 与 LDL（1.5mg/mL）配合物的平均发射寿命分别为 15 和 46 微秒。还介绍了对一些金属干扰物的研究。
