Continuous focusing, fractionation and extraction of anionic analytes in a microfluidic chip

Abstract

Selective extraction of concentrated anionic analytes focused via ion concentration polarization focusing.

Droplet encapsulation of electrokinetically-focused analytes without loss of resolution

“…The extraction of analytes electrokinetically focused via ion concentration polarization focusing (ICPF) has been reported before by our group 1,2 and a number of other researchers. [3][4][5][6][7][8] Continuous extraction methods such as our previous work and the work 2 of Kwak et al 5 suffer from low preconcentration rates.…”

“…5,17,[21][22][23][24][25][26][27][28][29][30] We refer the reader to a short theoretical background of ICPF in the ESI † in order to define the requirements of the droplet generator. For a deeper theoretical background of ICPF the reader is referred to our previous work 1 or the work of Ouyang et al 31 and the more recent work of Gong et al 6,7 There are two operating modes in ICPF namely peak and plateau mode. In peak mode analytes that are in low concentration compared to the bulk electrolyte will form a Gaussian peak when they concentrate by ICPF.…”

“…In peak mode analytes that are in low concentration compared to the bulk electrolyte will form a Gaussian peak when they concentrate by ICPF. In our previous work 1 we derived the variance σ i 2 [m 2 ] of this Gaussian distribution as…”

Cation‐Specific Electrokinetic Separations Using Prussian Blue Intercalation Reactions

“…[25][26][27] The electric field gradient associated with ICP has also been used for dielectrophoresis of cells, [14,28,29] salt water desalination, [17,[30][31][32] and analyte enrichment. [33] Analytes such as charged fluorophores, [1,34,35] microparticles, [23,36] and proteins [37,38] have all been enriched, with up to a million-fold enrichment factor in one case. [16] A few years ago, our group introduced an electrochemical variant of ICP called faradaic ICP (fICP).…”

“…The electric field gradient associated with ICP has also been used for dielectrophoresis of cells, salt water desalination, and analyte enrichment . Analytes such as charged fluorophores, microparticles, and proteins have all been enriched, with up to a million‐fold enrichment factor in one case …”