Seo Joowon, Ha Sungjae, Kim Sung Jae
Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea.
ProvaLabs, Inc., Seoul 08826, Republic of Korea.
Langmuir. 2024 Aug 6;40(31):16443-16453. doi: 10.1021/acs.langmuir.4c01773. Epub 2024 Jul 24.
This work reports on experimental investigations into the operational parameters of nanoelectrokinetic purification and preconcentration, especially utilizing on ion concentration polarization (ICP). ICP as a nanoscale electrokinetic phenomenon has demonstrated promising advances in various fields utilizing an ion depletion zone (IDZ) with a steep electric field gradient inside the ICP layer. However, the inevitable electrokinetic instability occurring within the IDZ has posed a challenge in operating the ICP system stably. To address the need for a stable and efficient ICP operation in various devices and applications, we propose an operational strategy along with conducted research to determine optimal operating ranges. In order to investigate the operational parameters, a unit voltage () is introduced as the threshold for initiating ICP. We examined the applicability of across various operating ranges to ensure its effectiveness and versatility. In ICP purification, we categorize three modes (steady, burst, and unsteady) based on IDZ expansion and stability under varying and flow rate conditions, presenting optimal operational conditions that minimize the voltage margin. In ICP preconcentration, a systematic investigation is conducted to observe the influence of background electrolyte concentration and voltage conditions on preconcentration efficiency, offering insights into the correlation between preconcentration factor, electrical conditions, and preconcentration time. Therefore, this research would contribute to the practical understanding of nanoelectrokinetics, providing insight into experimental designs. These findings are expected to offer valuable guidance to researchers aiming to utilize ICP's potential across a spectrum of applications, from purification to preconcentration, in the realm of micro/nanofluidic systems.
本工作报道了对纳米电动净化和预浓缩操作参数的实验研究，特别是关于离子浓度极化（ICP）的应用。ICP作为一种纳米级电动现象，利用ICP层内具有陡峭电场梯度的离子耗尽区（IDZ），在各个领域都展现出了有前景的进展。然而，IDZ内不可避免地会出现电动不稳定性，这给稳定运行ICP系统带来了挑战。为了满足在各种设备和应用中实现稳定高效的ICP操作的需求，我们提出了一种操作策略，并开展了相关研究以确定最佳操作范围。为了研究操作参数，引入了单位电压（）作为启动ICP的阈值。我们研究了在各种操作范围内的适用性，以确保其有效性和通用性。在ICP净化过程中，我们根据IDZ在不同和流速条件下的扩展和稳定性，将其分为三种模式（稳定、突发和不稳定），并给出了使电压裕度最小化的最佳操作条件。在ICP预浓缩方面，我们进行了系统研究，以观察背景电解质浓度和电压条件对预浓缩效率的影响，从而深入了解预浓缩因子、电学条件和预浓缩时间之间的相关性。因此，本研究将有助于对纳米电动学的实际理解，为实验设计提供见解。这些发现有望为旨在利用ICP在微纳流体系统领域从净化到预浓缩等一系列应用中的潜力的研究人员提供有价值的指导。
