Renewable pH cross-sensitive potentiometric heparin sensors with incorporated electrically charged H+ ionophores.
Renewable pH cross-sensitive potentiometric heparin sensors with incorporated electrically charged H+ ionophores.
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DOI：
10.1021/ac990387s
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发表时间：
1999-09
影响因子：
7.4
通讯作者：
S. Mathison;E. Bakker
中科院分区：
文献类型：
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作者：
S. Mathison;E. Bakker
较早开发出基于聚合物膜的电位传感器，为聚离子（例如肝素）提供快速、直接的分析方法，肝素是一种天然抗凝剂，用于在心血管手术期间预防血栓形成。这些肝素传感器是不可逆的，需要在测量之间进行膜更新程序，这目前阻止了传感器用于连续监测血液肝素。这里展示了一种新开发的肝素传感器，可提供替代且更实用的膜更新方法。带电的 H+ 离子载体 5-(十八烷酰氧基)-2-(4-硝基苯基偶氮)-苯酚 (ETH 2412) 作为附加离子载体并入肝素传感膜中。该膜仅在低 H+ 浓度下对 pH 做出响应，而样品阴离子在生理 pH 值下与 H+ 离子共萃取到膜中。因此，在生理 pH 值的缓冲样品中，传感器将通过与氯阴离子的离子交换机制对肝素做出响应。 pH 交叉敏感肝素感应膜对生理 pH 和 Cl 水平的水样中以及未稀释的全血中的肝素具有出色的电位响应，且不会损失肝素响应。膜的更新是通过适度提高样品的 pH 值来实现的，导致肝素与 H+ 离子一起扩散出膜。与经典系统相比，重现性得到改善，标准偏差小于 1 mV。与之前建立的肝素传感器中用于剥离肝素的高 NaCl 浓度不同，这里使用的 pH 变化最终可以在样品膜界面局部进行，从而使传感器能够用于血液中肝素的自动长期监测。提出了一个理论模型来解释实验结果。
Polymer membrane-based potentiometric sensors have been developed earlier to provide a rapid and direct method of analysis for polyions such as heparin, a natural anticoagulant administered to prevent thrombus formation during cardiovascular surgery. These heparin sensors are irreversible, requiring a membrane renewal procedure between measurements which currently prevents the sensors from being used for continuous monitoring of blood heparin. A newly developed heparin sensor is shown here to allow an alternate and more practical method of membrane renewal. The electrically charged H+ ionophore 5-(octadecanoyloxy)-2-(4-nitrophenylazo)-phenol (ETH 2412) is incorporated as an additional ionophore into a heparin-sensing membrane. This membrane will respond to pH only at low H+ concentrations, while sample anions are coextracted with H+ ions into the membrane at physiological pH. In buffered samples at physiological pH, the sensors will therefore respond to heparin via an ion-exchange mechanism with chloride anions. The pH cross-sensitive heparin-sensing membranes are shown to give an excellent potentiometric response toward heparin in aqueous samples at physiological pH and Cl-levels as well as in undiluted whole blood with no loss of heparin response. The membrane renewal is accomplished by moderately increasing the pH of the sample, causing heparin to diffuse out of the membrane with H+ ions. Reproducibilities are, with less than 1 mV standard deviation, improved over the classical system. Unlike the high NaCl concentration used to strip heparin from the previously established heparin sensor, the pH change used here could ultimately be performed locally at the sample-membrane interface, allowing the sensor to be used for automated long-term monitoring of heparin in blood. A theoretical model is presented to explain the experimental results.