School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-2710, USA.
Anal Chim Acta. 2010 Feb 5;659(1-2):243-50. doi: 10.1016/j.aca.2009.11.030. Epub 2009 Nov 18.
A new miniaturization approach to create micro- and nanoscale ion selective electrodes (ISEs) was demonstrated and the concept tested with an environmentally relevant chromate-selective membrane consisting of 7.7:62.2:31.1 wt % Aliquat336:2-NPOE:PVC. Apertures of 100 nM and 30 microM dimensions were made using MEMS fabrication techniques and functionalized through a macroscale application of solvent polymeric membrane. Performance studies for the microscale ISE showed a response slope of -58.6+/-5.6 mV decade(-1) and limit of detection (LOD) of 2.1 x 10(-5)+/-1.1 x 10(-5) M, versus -65.2+/-4.2 mV decade(-1) and 1.8 x 10(-5)+/-6 x 10(-6) M for the nanoscale ISE. This was consistent with control studies with carefully conditioned coated wire electrodes, which demonstrated a response slope of -61.7+/-2.4 mV decade(-1) and a LOD of 3.0 x 10(-6)+/-1 x 10(-6) M. Response times for the best micro- and nanoscale ISEs were in the 10-20 s timeframe. Electrical resistance measurements were in the GOmega range for the microscale ISEs and nanoscale ISEs. Appropriate ISE geometry was confirmed through AFM measurements and calculations based on electrical properties for micro- and nanoscale apertures. These micro- and nanoscale ISEs are expected to have significant impact in the field of microscale analytical processes.
一种新的微型化方法被用于创建微纳米尺度的离子选择性电极（ISE），并通过一种由 7.7:62.2:31.1wt%Aliquat336:2-NPOE:PVC 组成的环境相关铬酸盐选择性膜来测试该概念。通过使用 MEMS 制造技术制造出 100nm 和 30μm 尺寸的孔，并通过宏观应用溶剂聚合膜进行功能化。对微尺度 ISE 的性能研究表明，响应斜率为-58.6+/-5.6 mV 每 decade(-1)，检测限（LOD）为 2.1 x 10(-5)+/-1.1 x 10(-5) M，而纳米尺度 ISE 的响应斜率为-65.2+/-4.2 mV 每 decade(-1)，LOD 为 1.8 x 10(-5)+/-6 x 10(-6) M。这与经过精心处理的涂层线电极的对照研究一致，该研究表明响应斜率为-61.7+/-2.4 mV 每 decade(-1)，LOD 为 3.0 x 10(-6)+/-1 x 10(-6) M。最佳微纳米尺度 ISE 的响应时间在 10-20 s 范围内。微尺度 ISE 的电阻测量值在 GOmega 范围内，纳米尺度 ISE 的电阻测量值在 GOmega 范围内。通过 AFM 测量和基于微纳米孔径电性能的计算，确认了适当的 ISE 几何形状。这些微纳米尺度的 ISE 有望在微尺度分析过程领域产生重大影响。
