Fundamentals of Micellar Electrokinetic Capillary Chromatography

Powell, A. Craig; Swaile, David F.; Cole, Roderic O.

doi:10.1016/b978-0-12-304250-7.50011-0

Cited by 24 publications

(15 citation statements)

References 68 publications

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“…In MECC, similar observations have been made [13,20,24,28]. In this study we have examined the effects of adding deuterated organic solvents to a phosphate-borate buffer containing SDS at pH or pD 7.…”

Section: Deuterated Solventssupporting

confidence: 55%

Micellar electrokinetic chromatographic studies in D₂O based buffer solutions

et al. 1994

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The addition of deuterium oxide or organic solvents to surfactant-based electrolytes is an effective method for improving resolution in micellar electrokinetic capillary chromatography (MECC). Buffers containing phosphate, boric acid and sodium dodecyl sulphate at pH or pD 7 in the presence and absence of deuterated and non-deuterated solvents were used to separate some hydrophobic compounds covering a range of octanol-water partition coefficients (log P). Significant improvements in resolution of the more hydrophobic compounds were achieved by using mixtures of heavy water and deuterated methanol, instead of water and methanol. Quantitative structure-retention relationships were also derived to provide a better understanding of the intermolecular interactions that contribute to the separation of analytes in MECC. Multiple regression analysis has shown that capacity factors were significantly related to both log P and molecular refractivity. The latter is a measure of the molecular volume of analytes and is related to their ability to undergo dispersive interactions with the micellar components.

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Section: Deuterated Solventssupporting

confidence: 55%

Micellar electrokinetic chromatographic studies in D₂O based buffer solutions

et al. 1994

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“…Pre-column and post-column fluorescence labeling can greatly extend applications [ 121. However, these procedures have inherent problems (e.g., severe band-broadening with post-column derivatization) that can be exacerbated when CE is the mode of separation [12,14]. Moreover, when the analytes of interest are biopolymers, with many potential sites for labeling, the pre-column labeling process can destroy the integrity of the analyte band by forming multiple products.…”

Section: Introductionmentioning

confidence: 97%

Evaluation of on‐column labeling with intercalating dyes for fluorescence detection of DNA fragments separated by capillary electrophoresis

Clark¹

1993

J Microcolumn Separations

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Abstract. The analytical figures of merit of laser-excited fluorescence detection of DNA restriction fragments, based on the enhanced fluorescence of selected dyes upon intercalation, are presented. The fragments present in a 4x174 Hae I11 digest are efficiently separated by capillary electrophoresis employing methyl cellulose as a sizesieving reagent. On-column DNA labeling is accomplished by adding either ethdium bromide (EB) or POPO-3 iodide (POPO-3) to the electrophoretic running buffer. Experimental parameters that are evaluated include type of laser (helium-cadmium at 325 nm or helium-neon at 543 nm) and laser power, dye type and concentration, pre-injection labeling procedure, and applied field. Calibration plots are linear over two orders of magnitude in DNA concentration. Limits of detection are in the low-to-mid femtogram injected range for the individual fragments, with the POPO-3 providing slightly lower values. Both dyes exhibit large increases in fluorescence quantum efficiency upon intercalation and contribute little or nothing to the observed optical background. Detectability with the dyes is enhanced by a spectral shift upon intercalation. Signal intensities increase with DNA fragment size in approximately a linear fashion. Intercalation by the dyes also influences mobility and the resolution of the fragments studied.

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“…On the other hand, for very hydrophobic compounds, MEKC with SDS is often insufficiently selective. 3,4 The hydrophobic compounds tend to be absorbed virtually completely into the micelles; in that case the selectivity is lost because all compounds are migrating with the velocity of the micelles. Several methods have been proposed to expand the application range of MEKC to more hydrophobic compounds: the use of surfactants with a hydrophobicity lower than SDS such as cholic acid or derivatives, 5 or the addition of compounds to the BGE that interact with the analytes in the aqueous phase such as cyclodextrins, 6 can be used to introduce a shift in the distribution equilibrium toward the aqueous phase.…”

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confidence: 99%

Mechanism of Electrokinetic Separations of Hydrophobic Compounds with Sodium Dodecyl Sulfate in Acetonitrile−Water Mixtures

1997

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The effect of the addition of 0−70% (v/v) acetonitrile (AcCN) as organic modifier, into a buffer solution containing 0−60 mmol L-1 sodium dodecyl sulfate (SDS), on the electrokinetic behavior of neutral hydrophobic compounds has been studied experimentally. The effective mobilities of the hydrophobic compounds sharply decreased above a certain AcCN concentration, depending to some extent on the SDS concentration. In solutions with up to 40% AcCN, with SDS concentrations below the literature values of the critical micelle concentration, neutral hydrophobic analytes still showed a considerable electrophoretic mobility. The observed mobilities were too high to be attributed to solvophobic interaction of the analytes with single SDS ions. From conductivity measurements, a strong indication was found that increasing the fraction of AcCN in the SDS solution does not lead to a complete disintegration of the micelles. Even with high AcCN concentrations, the mechanism of the separation was found to be a distribution between the aqueous phase and micelle-like SDS aggregates. The influence of the addition of AcCN on the mobilities could be explained as the combined effect of a decrease of the micellar volume fraction, a change of the micellar properties, and a decrease of the distribution constants of the analytes.

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Fundamentals of Micellar Electrokinetic Capillary Chromatography

Cited by 24 publications

References 68 publications

Micellar electrokinetic chromatographic studies in D₂O based buffer solutions

Micellar electrokinetic chromatographic studies in D₂O based buffer solutions

Evaluation of on‐column labeling with intercalating dyes for fluorescence detection of DNA fragments separated by capillary electrophoresis

Mechanism of Electrokinetic Separations of Hydrophobic Compounds with Sodium Dodecyl Sulfate in Acetonitrile−Water Mixtures

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Fundamentals of Micellar Electrokinetic Capillary Chromatography

Cited by 24 publications

References 68 publications

Micellar electrokinetic chromatographic studies in D2O based buffer solutions

Micellar electrokinetic chromatographic studies in D2O based buffer solutions

Evaluation of on‐column labeling with intercalating dyes for fluorescence detection of DNA fragments separated by capillary electrophoresis

Mechanism of Electrokinetic Separations of Hydrophobic Compounds with Sodium Dodecyl Sulfate in Acetonitrile−Water Mixtures

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Micellar electrokinetic chromatographic studies in D₂O based buffer solutions

Micellar electrokinetic chromatographic studies in D₂O based buffer solutions