Hu Jinbo, Ho Kieu T, Zou Xu U, Smyrl William H, Stein Andreas, Bühlmann Philippe
Department of Chemistry, University of Minnesota , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
Anal Chem. 2015 Mar 3;87(5):2981-7. doi: 10.1021/ac504556s. Epub 2015 Feb 10.
Reference electrodes are used in almost every electroanalytical measurement. Here, all-solid-state reference electrodes are described that employ colloid-imprinted mesoporous (CIM) carbon as solid contact and a poly(vinyl chloride) reference membrane to contact the sample. Such a reference membrane is doped with a moderately hydrophilic ionic liquid and a hydrophobic redox couple, leading to well-defined constant potentials at the interfaces of this membrane to the sample and to the solid contact, respectively. Due to the intrinsic properties of CIM carbon, reference electrodes with a CIM carbon solid contact exhibit excellent resistance to common interfering agents such as light and O2, with outstanding potential stability in continuous potentiometric measurements. The potential drift of CIM carbon-based reference electrodes without redox couple is as low as 1.7 μV/h over 110 h, making them the most stable all-solid-state reference electrodes reported so far. To demonstrate the compatibility of CIM carbon-based reference electrodes with miniaturized potentiometric systems, these reference electrodes were integrated into paper-based potentiometric sensing devices, successfully replacing the conventional reference electrode with its reference electrolyte solution. As a proof of concept, disposable paper-based Cl(-) sensing devices that contain stencil-printed Ag/AgCl-based Cl(-) selective electrodes and CIM carbon-based reference electrodes were constructed. These sensing devices are inexpensive, easy to use, and offer highly reproducible Cl(-) measurements with sample volumes as low as 10 μL.
几乎在每一项电分析测量中都会使用参比电极。在此，将描述全固态参比电极，其采用胶体印迹介孔（CIM）碳作为固体接触材料，并使用聚氯乙烯参比膜与样品接触。这种参比膜掺杂有适度亲水性离子液体和疏水性氧化还原对，分别在该膜与样品以及与固体接触的界面处产生明确的恒定电位。由于CIM碳的固有特性，具有CIM碳固体接触的参比电极对常见干扰剂（如光和O2）具有出色的抗性，在连续电位测量中具有出色的电位稳定性。不含氧化还原对的基于CIM碳的参比电极在110小时内的电位漂移低至1.7 μV/h，使其成为迄今为止报道的最稳定的全固态参比电极。为了证明基于CIM碳的参比电极与小型化电位系统的兼容性，将这些参比电极集成到纸质电位传感装置中，成功地用其参比电解质溶液取代了传统参比电极。作为概念验证，构建了包含模板印刷的基于Ag/AgCl的Cl(-)选择性电极和基于CIM碳的参比电极的一次性纸质Cl(-)传感装置。这些传感装置价格低廉、易于使用，并且能够以低至10 μL的样品体积提供高度可重复的Cl(-)测量结果。
