On-line isotachophoresis. A selective sample pretreatment prior to column liquid chromatographic analysis

Hendriks, Pieter J. M.; Claessens, H.A.; Noij, Th.H.M; Everaerts, F.M.; Cramers, C.A.M.G.

doi:10.1007/bf02262245

Cited by 12 publications

(3 citation statements)

References 32 publications

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“…Additionally, we focus on detection systems for analytical ITP and do not review methods that couple ITP purification, focusing, and separation with downstream analyses such as zone electrophoresis, mass spectroscopy, or chromatography. See refs , , , and − for discussions on the latter topic. Also refer to for a series of ITP tutorial videos showing protocols for carrying out on-chip ITP experiments including buffer and chip preparation, electric field control, and imaging.…”

Section: Experimental Tools and Detection Methodsmentioning

confidence: 99%

Isotachophoresis: Theory and Microfluidic Applications

Ramachandran

Santiago

2022

Chem. Rev.

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Isotachophoresis (ITP) is a versatile electrophoretic technique that can be used for sample preconcentration, separation, purification, and mixing, and to control and accelerate chemical reactions. Although the basic technique is nearly a century old and widely used, there is a persistent need for an easily approachable, succinct, and rigorous review of ITP theory and analysis. This is important because the interest and adoption of the technique has grown over the last two decades, especially with its implementation in microfluidics and integration with on-chip chemical and biochemical assays. We here provide a review of ITP theory starting from physicochemical first-principles, including conservation of species, conservation of current, approximation of charge neutrality, pH equilibrium of weak electrolytes, and so-called regulating functions that govern transport dynamics, with a strong emphasis on steady and unsteady transport. We combine these generally applicable (to all types of ITP) theoretical discussions with applications of ITP in the field of microfluidic systems, particularly on-chip biochemical analyses. Our discussion includes principles that govern the ITP focusing of weak and strong electrolytes; ITP dynamics in peak and plateau modes; a review of simulation tools, experimental tools, and detection methods; applications of ITP for on-chip separations and trace analyte manipulation; and design considerations and challenges for microfluidic ITP systems. We conclude with remarks on possible future research directions. The intent of this review is to help make ITP analysis and design principles more accessible to the scientific and engineering communities and to provide a rigorous basis for the increased adoption of ITP in microfluidics.

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Section: Experimental Tools and Detection Methodsmentioning

confidence: 99%

Isotachophoresis: Theory and Microfluidic Applications

Ramachandran

Santiago

2022

Chem. Rev.

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“…Concerning ITP and HPLC, these techniques are based on different physical properties which resulting in a powerful separation. In the literature, only limited numbers of papers have dealt with the combination of isotachophoresis with liquid chromatography [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

High-performance liquid chromatography determination of phenolic components in wine using off-line isotachophoretic pretreatment

Sladkovský

Solich

Urbánek

2004

Journal of Chromatography A

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“…In the steady state the sample components migrate with equal velocity between leading and terminating electrolytes with a concentration adapted to that of the leading ions according to the Kohlrausch regulatory function (KRF) and all sample zone boundaries are sharp as a result of the self-correcting properties [1]. Because of these properties ITP is often used, besides analytical applications, as sample pretreatment and preconcentration technique (stacking), both offand on-line, with capillary zone electrophoresis (CZE) [4± 7] and high performance liquid chromatography (HPLC) [8]. If ITP is applied in combination with CZE, a destacking procedure must be applied for the separation process to take place along a zone electrophoretic way and a great deal of the gain will be lost.…”

mentioning

confidence: 99%

Window optimization in isotachophoresis superimposed on capillary zone electrophoresis

Beckers

2000

Electrophoresis

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A sample stacking procedure to which a specific combination of electrolyte solutions is applied is isotachophoresis (ITP) superimposed on capillary zone electrophoresis (CZE), a so-called ITP/CZE system. In ITP/CZE some components migrate in an ITP fashion on top of a background electrolyte, and the other analytes migrate in a zone electrophoretic manner. For such a system, the leading electrolyte consists of a mixture of an ionic species, L1, of high mobility (the leading ion of the ITP system), an ionic species, L2, of low mobility (the coions of the CZE system), and a buffering counter-ionic species, whereas the terminating solution only contains the ionic species L2 and the buffering counterions. The zones of the components migrating in the ITP/CZE mode are sharp owing to the self-correcting properties of the zones and the concentrations of the L1 ions of the system. Mobility windows can be calculated, indicating which ions can migrate in the ITP/CZE mode. In this article mobility windows are calculated by applying both strong and weak acids as L1 and L2 ions and it appears that mobility windows can be optimized by chosing different ratios of L1 and L2 as well as different pH values. It is possible to construct very narrow mobility windows, and thereby choose which component of a sample solution can be concentrated, and to what concentration, in a very selective way. The big advantage of ITP/CZE compared with applications such as transient ITP and transient stacking is that the stacked sample ionic species migrate in the ITP mode during the whole experiment; furthermore, they do not destack. Experimentally obtained electropherograms validate the calculated mobility windows for the ITP/CZE mode.

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On-line isotachophoresis. A selective sample pretreatment prior to column liquid chromatographic analysis

Cited by 12 publications

References 32 publications

Isotachophoresis: Theory and Microfluidic Applications

Isotachophoresis: Theory and Microfluidic Applications

High-performance liquid chromatography determination of phenolic components in wine using off-line isotachophoretic pretreatment

Window optimization in isotachophoresis superimposed on capillary zone electrophoresis

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