Exploring Gradients in Electrophoretic Separation and Preconcentration on Miniaturized Devices

Abstract

Over the last two decades, miniaturization, integration, and automation have made microfluidic systems popular. Core to advances in microfluidics are numerous electrophoretic separation and preconcentration strategies, some finding their origins on bench-top systems. Among them, gradient-based strategies are especially effective in addressing sensitivity challenges. This review introduces several gradient-based techniques according to a broad definition, including conductivity, field, and concentration, organized by the method of gradient generation. Each technique is introduced and described, and recent seminal advances explored.

Recent developments in capillary and microchip electroseparations of peptides (2015–mid 2017)

“…. Special reviews and papers deal with the particular sample clean‐up techniques, such as SPE , solid‐phase microextraction (SPME) , electromembrane extraction , selective electromembrane extraction based on isoelectric point , magneto‐immuno capture , and on‐line electrodriven sample‐stacking techniques . The latter electrodriven procedures include field amplified sample stacking , field enhanced or field‐amplified sample injection (FESI or FASI) ; large volume sample stacking (LVSS) , transient‐ITP (t‐ITP) , multiple capillary ITP (CITP) with repetitive hydrodynamic injection , dynamic pH junction , electrokinetic supercharging , and sweeping .…”

Recent progress of sample stacking in capillary electrophoresis (2016–2018)

“…During the reviewed period, no other methodological review on electrophoretic sample stacking appeared; the below mentioned reviews have broader or narrower scopes, or are focused on specific aspects. General reviews were aimed at enrichment techniques and enhancement of sensitivity in CE , their application in chiral CE , in CE‐MS and in the analysis of alkaloids . Electrophoretic stacking was also included in specialized reviews on CE analyses of peptides and proteins , pharmaceuticals , pesticides , antibiotics , food , and biologically important thiols .…”

Transverse migration and microfluidic concentration of DNA using Newtonian buffers

“…7 Many methods of processing DNA on microfluidic platforms have utilized immobilization or capture. [8][9][10] General methods for concentrating analytes that utilize gradients in the buffers or fields 11,12 have been used to preconcentrate DNA, including temperature gradient focusing, 13 rheotaxis, 14 and isotachophoresis. 15 Electrokinetic trapping of DNA using membranes [16][17][18][19] and dielectrophoretic trapping of DNA in a microfluidic channel equipped with an array of electrodes have also been demonstrated.…”