Organic Synthesis, Electrochemistry & Natural Product Research Unit, Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Engineering Science Classroom, Darunsikkhalai School, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
Analyst. 2022 Oct 10;147(20):4517-4524. doi: 10.1039/d2an01220k.
Here, we developed a microfluidic paper device by combining ion-selective electrodes (ISE) and a distance-based paper device (dPAD) for simultaneous potentiometric and colorimetric detection of urine electrolytes including K, Na and Cl. The working and reference electrode zones were coated with polystyrene as a non-ionic polymer to improve hydrophobic properties on the paper surface for fabrication of K-ISE and Na-ISE. The layer of polymer coating was optimized to enhance the sensitivity of the ISEs. Under optimized conditions, the electrode surfaces were modified with carbon black to improve the electrochemical characteristics of the ISEs. The ISEs showed good performance with sensitivities of 54.14 ± 3.94 mV per decade and 55.08 ± 1.15 mV per decade for K and Na within the linear concentration range 0.100 mM-100 mM K and 5 mM-1 M Na, respectively. The limits of detection (LOD) were 0.05 mM and 1.36 mM for K and Na, respectively. The linear working range of Cl was 0.50 to 50 mM and the LOD and limit of quantification (LOQ) were found to be 0.16 ± 0.05 mM (3SD) and 0.53 ± 0.05 mM (10SD), respectively. The dual-mode ISE-dPAD was validated in human urine and recoveries were obtained as 90-108%, 94-105%, and 90-96% for K, Na, and Cl, respectively, showing successful application of the developed device in a complex matrix. The ISE-dPAD has advantages including low-cost ($ 0.33 per test), eco-friendly, portability, simple operation, the need of low sample volume (100 μL), and simultaneous analysis on a single device.
在这里，我们开发了一种微流控纸装置，将离子选择性电极 (ISE) 和基于距离的纸装置 (dPAD) 结合在一起，用于同时对尿液电解质（包括 K、Na 和 Cl）进行电势和比色检测。工作电极和参比电极区域涂有聚苯乙烯作为非离子聚合物，以改善纸表面的疏水性，从而制造 K-ISE 和 Na-ISE。优化了聚合物涂层的层以提高 ISE 的灵敏度。在优化条件下，电极表面用炭黑修饰以改善 ISE 的电化学特性。ISE 在优化条件下表现出良好的性能，K 的灵敏度为 54.14 ± 3.94 mV/decade，Na 的灵敏度为 55.08 ± 1.15 mV/decade，线性浓度范围分别为 0.100 mM-100 mM K 和 5 mM-1 M Na。K 和 Na 的检测限 (LOD) 分别为 0.05 mM 和 1.36 mM。Cl 的线性工作范围为 0.50 至 50 mM，LOD 和定量限 (LOQ) 分别为 0.16 ± 0.05 mM（3SD）和 0.53 ± 0.05 mM（10SD）。双模式 ISE-dPAD 在人尿中进行了验证，回收率分别为 K、Na 和 Cl 的 90-108%、94-105%和 90-96%，表明该装置在复杂基质中的成功应用。ISE-dPAD 具有成本低（每个测试 0.33 美元）、环保、便携、操作简单、需要低样品量（100 μL）以及在单个设备上同时分析等优点。
