Chun Honggu
Department of Biomedical Engineering, Korea University, Seoul, Korea.
Electrophoresis. 2018 Feb;39(3):521-525. doi: 10.1002/elps.201700373. Epub 2017 Nov 24.
Ion-permselective nanochannel-based sample preconcentration or electropreconcentration has been demonstrated as an effective technique for concentrating charged analytes at the interface between a micro- and nanochannel. The anion-selective electropreconcentration involves extraction of hydroxide in the preconcentrated sample plug, resulting in pH decrease. We investigated the pH change in a microchannel using charged pH indicators with different conditions including running buffer pH, sample channel electric field, and salt concentration. The anion-selective preconcentration showed pH decrease from 11 to under 7 in the preconcentrated sample plug. Therefore, careful design and interpretation are required with pH-dependent experiments such as analyzing enzyme or antibody characteristics. The pH change could be mitigated by reducing the sample channel electric field and/or increasing salt concentration in the buffer.
基于离子选择性纳米通道的样品预浓缩或电预浓缩已被证明是一种在微通道和纳米通道界面浓缩带电分析物的有效技术。阴离子选择性电预浓缩涉及在预浓缩样品塞中提取氢氧根，导致pH值降低。我们使用带电荷的pH指示剂，在不同条件下（包括运行缓冲液pH值、样品通道电场和盐浓度）研究了微通道中的pH变化。阴离子选择性预浓缩显示预浓缩样品塞中的pH值从11降至7以下。因此，对于诸如分析酶或抗体特性等依赖pH的实验，需要仔细设计和解读。通过降低样品通道电场和/或增加缓冲液中的盐浓度，可以减轻pH变化。
