Faculdade de Ciências Exatas e Tecnologia , Universidade Federal da Grande Dourados , Rodovia Dourados-Itahum, km 12 , 79804-970 Dourados , Mato Grosso do Sul , Brazil.
National Institute for Alternative Technologies of Detection, Toxicological Evaluation and Removal of Micropollutants and Radioactives , Institute of Chemistry, Universidade Estadual Paulista , P.O. Box 355 , 14800-900 Araraquara , São Paulo , Brazil.
Anal Chem. 2018 Sep 18;90(18):10917-10926. doi: 10.1021/acs.analchem.8b02438. Epub 2018 Aug 31.
A newly configured electrochemical flow cell to be used for (end-channel) amperometric detection in a microfluidic device is presented. The design was assembled to place the reference electrode in a separated compartment, isolated from the flow in the microchannel, while the working and counter electrodes remain in direct contact with both compartments. Moreover, a three-dimensional coil-shaped microfluidic device was fabricated using a nonconventional protocol. Both devices working in association enabled us to solve the drawback caused by the discrete injection when the automatic micropipette was used. The high performance of the proposed electrochemical flow cell was demonstrated after in situ modifying the surface of the platinum working electrode with surfactant (e.g., using Tween 20 at 0.10%). As the reference electrode remained out of contact with the flowing solution, there was no trouble by air bubble formation (generated by accidental insertion or by presence of surfactants) throughout the measurements. This device was characterized regarding its analytical performance by evaluating the amperometric detection of acetaminophen, enabling determination from 6.60 to 66.0 μmol L. This issue is important since at high concentration (e.g., as assessed in clinical analysis) the acetaminophen is known to passivate the working electrode surfaces by electrogenerated products, impairing the accuracy of the electrochemical measurements.
本文介绍了一种新配置的电化学流通池，用于微流控装置中的（末端通道）电流安培检测。该设计将参比电极组装在一个分离的隔室中，与微通道中的流动隔离，而工作电极和对电极则与两个隔室保持直接接触。此外，还使用非传统方法制造了三维螺旋形微流控器件。两个关联工作的器件使我们能够解决自动微量进样器使用时离散注入引起的缺陷。在原位用表面活性剂（例如 0.10%的吐温 20）对铂工作电极进行表面修饰后，证明了所提出的电化学流通池具有优异的性能。由于参比电极与流动溶液保持不接触，因此在整个测量过程中不会因气泡形成（由意外插入或表面活性剂的存在引起）而产生问题。通过评估对乙酰氨基酚的安培检测，评估了该器件的分析性能，可在 6.60 至 66.0 μmol L 的范围内进行测定。这个问题很重要，因为在高浓度下（例如在临床分析中评估），电生成产物会使工作电极表面钝化，从而影响电化学测量的准确性。
