Revisiting Electroosmotic Flow: An Important Parameter Affecting Separation in Capillary and Microchip Electrophoresis

Ahmadzadeh, Hossein; Prescott, M.; Muster, Nemone; Stoyanov, Alexandre

doi:10.1080/00986440701569226

Cited by 13 publications

(6 citation statements)

References 25 publications

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“…No excessive heating was observed within this range and thus no adjustment of voltage was needed (30 kV still at the linear part of Ohm's plot with 50 mM BGE). At higher ionic strengths the thickness of the electrical double layer on the wall of the capillary decreases, resulting in a decreased EOF which was observed with both of the PECs in this study (see Supporting Information Fig. 2).…”

Section: Resultssupporting

confidence: 63%

Novel cationic polyelectrolyte coatings for capillary electrophoresis

et al. 2015

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The use of bare fused silica capillary in CE can sometimes be inconvenient due to undesirable effects including adsorption of sample or instability of the EOF. This can often be avoided by coating the inner surface of the capillary. In this work, we present and characterize two novel polyelectrolyte coatings (PECs) poly(2-(methacryloyloxy)ethyl trimethylammonium iodide) (PMOTAI) and poly(3-methyl-1-(4-vinylbenzyl)-imidazolium chloride) (PIL-1) for CE. The coated capillaries were studied using a series of aqueous buffers of varying pH, ionic strength, and composition. Our results show that the investigated polyelectrolytes are usable as semi-permanent (physically adsorbed) coatings with at least five runs stability before a short coating regeneration is necessary. Both PECs showed a considerably decreased stability at pH 11.0. The EOF was higher using Good's buffers than with sodium phosphate buffer at the same pH and ionic strength. The thickness of the PEC layers studied by quartz crystal microbalance was 0.83 and 0.52 nm for PMOTAI and PIL-1, respectively. The hydrophobicity of the PEC layers was determined by analysis of a homologous series of alkyl benzoates and expressed as the distribution constants. Our result demonstrates that both PECs had comparable hydrophobicity, which enabled separation of compounds with log Po/w > 2. The ability to separate cationic drugs was shown with β-blockers, compounds often misused in doping. Both coatings were also able to separate hydrolysis products of the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-ene acetate at highly acidic conditions, where bare fused silica capillaries failed to accomplish the separation.

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Section: Resultssupporting

confidence: 63%

Novel cationic polyelectrolyte coatings for capillary electrophoresis

et al. 2015

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“…If the EOF is strong enough, it will cause the bulk movement of all species towards the cathode. Therefore, if the detector is placed at the cathode, the migration order will be cations, neutrals, and then anions [31]. The magnitude of the EOF is a function of the zeta potential set up at the capillary wall.…”

Section: Microchip Electrophoresis: Technical Characteristics and Basmentioning

confidence: 99%

Microfluidics as a Novel Tool for Biological and Toxicological Assays in Drug Discovery Processes: Focus on Microchip Electrophoresis

et al. 2020

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The last decades of biological, toxicological, and pharmacological research have deeply changed the way researchers select the most appropriate ‘pre-clinical model’. The absence of relevant animal models for many human diseases, as well as the inaccurate prognosis coming from ‘conventional’ pre-clinical models, are among the major reasons of the failures observed in clinical trials. This evidence has pushed several research groups to move more often from a classic cellular or animal modeling approach to an alternative and broader vision that includes the involvement of microfluidic-based technologies. The use of microfluidic devices offers several benefits including fast analysis times, high sensitivity and reproducibility, the ability to quantitate multiple chemical species, and the simulation of cellular response mimicking the closest human in vivo milieu. Therefore, they represent a useful way to study drug–organ interactions and related safety and toxicity, and to model organ development and various pathologies ‘in a dish’. The present review will address the applicability of microfluidic-based technologies in different systems (2D and 3D). We will focus our attention on applications of microchip electrophoresis (ME) to biological and toxicological studies as well as in drug discovery and development processes. These include high-throughput single-cell gene expression profiling, simultaneous determination of antioxidants and reactive oxygen and nitrogen species, DNA analysis, and sensitive determination of neurotransmitters in biological fluids. We will discuss new data obtained by ME coupled to laser-induced fluorescence (ME-LIF) and electrochemical detection (ME-EC) regarding the production and degradation of nitric oxide, a fundamental signaling molecule regulating virtually every critical cellular function. Finally, the integration of microfluidics with recent innovative technologies—such as organoids, organ-on-chip, and 3D printing—for the design of new in vitro experimental devices will be presented with a specific attention to drug development applications. This ‘composite’ review highlights the potential impact of 2D and 3D microfluidic systems as a fast, inexpensive, and highly sensitive tool for high-throughput drug screening and preclinical toxicological studies.

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“…Reprinted from [68] with permission. [72,73], it should be noted that the time consumed in determining a for use in Eq. (35) for each particular electrolyte makes m EOF unsuitable for use as a routine temperature probe.…”

Section: Use Of L Eof As a Temperature Probementioning

confidence: 99%

Joule heating effects and the experimental determination of temperature during CE

Evenhuis

Haddad

2009

Electrophoresis

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Joule heating is ubiquitous in electrokinetic separations. This review is in two major parts. The first part documents the effects of Joule heating on the physical properties of the electrolyte and efficiency of separations and the second part focuses on advances in the determination of electrolyte temperatures that have been described in the literature over the past 5 years. The focus is on methods that can be applied by practitioners without the need for elaborate experimental requirements. Although the emphasis is on CE, many of the conclusions also apply to microfluidic formats.

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Revisiting Electroosmotic Flow: An Important Parameter Affecting Separation in Capillary and Microchip Electrophoresis

Cited by 13 publications

References 25 publications

Novel cationic polyelectrolyte coatings for capillary electrophoresis

Novel cationic polyelectrolyte coatings for capillary electrophoresis

Microfluidics as a Novel Tool for Biological and Toxicological Assays in Drug Discovery Processes: Focus on Microchip Electrophoresis

Joule heating effects and the experimental determination of temperature during CE

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