Detecting thiols in a microchip device using micromolded carbon ink electrodes modified with cobalt phthalocyanine
Detecting thiols in a microchip device using micromolded carbon ink electrodes modified with cobalt phthalocyanine
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DOI：
10.1039/b511153f
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发表时间：
2006-01-01
期刊：
影响因子：
4.2
通讯作者：
Martin, RS
中科院分区：
文献类型：
--
作者：
Kuhnline, CD;Gangel, MG;Martin, RS
本文介绍了一种化学修饰的碳墨水微电极的制备和评价，用于检测生物学上感兴趣的硫醇。检测硫醇，如同型半胱氨酸和半胱氨酸，对监测各种疾病状态是必要的。这些硫醇的生物学意义产生了小型化检测系统的需求，使便携式监测和定量结果成为可能。在这项工作中，我们利用一种微芯片装置，该装置结合了用酞菁钴修饰的微模碳墨水电极来检测硫醇。酞菁钴（CoPC）是一种电催化剂，可以降低硫醇氧化所需的电位。对CoPC/碳墨水的组成进行了优化，并利用基于微芯片的流动注射分析对微电极进行了表征。研究发现，CoPC降低了硫醇的过电位，但与直接安培检测相比，需要脉冲检测方案来不断地再生电催化剂表面，从而提高了峰的再现性和检测极限。使用脉冲的方法,半胱氨酸之间的线性响应展出10 - 250μM (r(2) = 0.9991)的检测极限(S / N = 3)为7.5μM,而同型半胱氨酸之间的线性响应展出10 - 500μM (r(2) = 0.9967)检测极限为6.9μM .最后,演示的能力来衡量硫醇在生物样品使用一个微芯片设备,CoPC-modified微电极是用于半胱氨酸的检测兔红细胞的存在。
This paper describes the fabrication and evaluation of a chemically modified carbon ink microelectrode to detect thiols of biological interest. The detection of thiols, such as homocysteine and cysteine, is necessary to monitor various disease states. The biological implications of these thiols generate the need for miniaturized detection systems that enable portable monitoring as well as quantitative results. In this work, we utilize a microchip device that incorporates a micromolded carbon ink electrode modified with cobalt phthalocyanine to detect thiols. Cobalt phthalocyanine (CoPC) is an electrocatalyst that lowers the potential needed for the oxidation of thiols. The CoPC/carbon ink composition was optimized for the micromolding method and the resulting microelectrode was characterized with microchip-based flow injection analysis. It was found that CoPC lowers the overpotential for thiols but, as compared to direct amperometric detection, a pulsed detection scheme was needed to constantly regenerate the electrocatalyst surface, leading to improved peak reproducibility and limits of detection. Using the pulsed method, cysteine exhibited a linear response between 10-250 mu M (r(2) = 0.9991) with a limit of detection (S/N = 3) of 7.5 mu M, while homocysteine exhibited a linear response between 10-500 mu M (r(2) = 0.9967) with a limit of detection of 6.9 mu M. Finally, to demonstrate the ability to measure thiols in a biological sample using a microchip device, the CoPC-modified microelectrode was utilized for the detection of cysteine in the presence of rabbit erythrocytes.