Recent advances in microscale extraction driven by ion concentration polarization

Microscale extraction offers several distinct advantages over bench-scale processes including increases in sample throughput, specificity, and efficiency. These attributes can be harnessed to improve the efficacy of assays, amplify analyte signals in sensors or purify samples. Recently, electrokinetic microextraction techniques have garnered increased attention owing to advantages such as control over mass transport, ease of actuation, and portability, which allow them to be readily incorporated into microscale and pointof-care devices. Ion concentration polarization (ICP) continuously creates an electric field gradient that can drive electrokinetic focusing. While the majority of articles on ICP have deliberated on analyte preconcentration, very few have ventured the subsequent extraction step - separation into another phase. The overarching aim of this review is to discuss recent developments in microfluidic extraction methods facilitated by ICP and the potential for their further advancement. Fundamental strategies used to achieve ICP-mediated extraction of distinct classes of analytes are discussed. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Microscale extraction offers advantages in sample throughput, specificity, and efficiency, which can be utilized to improve assays, sensor signals, and sample purification. Electrokinetic microextraction techniques have gained attention for their control over mass transport, ease of actuation, and portability, making them suitable for microscale and point-of-care devices. While most articles focus on analyte preconcentration using ion concentration polarization (ICP), few have explored the subsequent extraction step. This review discusses recent advancements in ICP-mediated microfluidic extraction methods and their potential for further development.