Gradient elution for micellar electrokinetic capillary chromatography

Balchunas, A. T.; Sepaniak, Michael J.

doi:10.1021/ac00158a003

Cited by 136 publications

(44 citation statements)

References 17 publications

(28 reference statements)

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“…Soon after its introduction, MEKC's potential for the separation of achiral ionic species with very similar electrophoretic mobilities as well as neutral and charged enantiomers was also recognized [5][6][7][8][9][10][11][12][13][14][15][16]. In parallel with the rapidly broadening areas of successful applications (e.g., pharmaceutical compounds [17][18][19][20][21], derivatized amino acids [22][23][24], water-and fat-soluble vitamins [25][26][27][28], and herbicides [29]) was the investigation of a wide variety of alternative PSPs including modified SDS micelles [30,31], non-SDS conventional micelles [2,32], mixed micelles [33,34], charged CDs [35], microemulsions [36], macrocyclic compounds [37], polymer micelles [38,39], bicelles [40,41], linear polymers [16], dendrimers [42], and pseudostationary ion-exchange phases [16].…”

Section: Introductionmentioning

confidence: 99%

Compositional effects on electrophoretic and chromatographic figures of merit in electrokinetic chromatography with cetyltrimethylammonium bromide/sodium octyl sulfate vesicles as the pseudostationary phase. Part 1: Effect of the phase ratio

et al. 2008

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The effect of the phase ratio on the electrophoretic and chromatographic properties of unilamellar vesicles comprised of cetyltrimethylammonium bromide (CTAB) and sodium octyl sulfate (SOS) was investigated in EKC. The surfactant concentration of the vesicles was 0.9, 1.2, 1.5, and 1.8% w/v, with a mole ratio of 1:3.66 (CTAB/SOS). Results were compared to those obtained using SDS micelles at concentrations of 1.0% (w/v, 35 mM) and 1.5% (52 mM). The CTAB/SOS vesicles (0.9-1.8% w/v) provided a significantly larger elution range (5.7 < or = t(ves)/t(0) < or = 8.7) and greater hydrophobic (methylene) selectivity (2.8 < or = alpha(CH2) < or = 3.1) than SDS micelles (3.1 < or = t(mc)/t(0) < or = 3.3; alpha(CH2) = 2.2). Whereas the larger elution range can be attributed to the 25% reduction in EOF due to the interaction of unaggregated CTAB cations and the negatively charged capillary wall, the higher methylene selectivity is likely due to the lower concentration of water expected in the CTAB/SOS vesicle bilayer compared to the Palisades layer of SDS micelles. For a given phase ratio, CTAB/SOS vesicles are somewhat less retentive than SDS micelles, although retention factors comparable to those observed in 1.0-1.5% SDS can be obtained with 1.5-1.8% CTAB/SOS. A linear relationship was observed between phase ratio and retention factor, confirming the validity of the phase ratio model for these vesicles. Unique polar group selectivities and positional isomer shape selectivities were obtained with CTAB/SOS vesicles, with both types of selectivities being nearly independent of the phase ratio. For four sets of positional isomers, the elution order was always para < ortho < meta. Finally, the thermodynamics of solute retention was qualitatively similar to that reported for other surfactant aggregates (micelles and microemulsions); the enthalpic contribution to retention was consistently favorable for all compounds, whereas the entropic contribution was favorable only to hydrophobic solutes.

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Section: Introductionmentioning

confidence: 99%

Compositional effects on electrophoretic and chromatographic figures of merit in electrokinetic chromatography with cetyltrimethylammonium bromide/sodium octyl sulfate vesicles as the pseudostationary phase. Part 1: Effect of the phase ratio

et al. 2008

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“…Applying the same instrumentation as in capillary zone electrophoresis, in MECC uncharged compounds can be separated based on differences in their partitioning between two phases, just as in chromatographic techniques. Since the introduction of MECC by Terabe et al [1,2], several authors have paid attention to the fundamental characteristics of this separation method [3,4] and to the effect of different separation parameters on the migration behavior [5][6][7][8][9][10][11]. Also the theoret-the solute in the micellar and the aqueous phase, and ts, tEO F and tMC are the migration times of the solute, the electroosmotic flow (EOF) and the micelles, respectively.…”

Section: Introductionmentioning

confidence: 99%

Parameters controlling the elution window and retention factors in micellar electrokinetic capillary chromatography

Muijselaar

Claessens

Cramers

1995

Journal of Chromatography A

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“…pH or flow gradients, or in the micellar electrokinetic separation mode by using organic modifier gradients [36,37]. However, most previous work on gradient separation in capillary electrophoretic separations has dealt with pH gradients.…”

Section: Background Electrolyte Gradientsmentioning

confidence: 99%

Advances in capillary electrophoresis

Deyl

Mikšı́k

Tagliaro

1998

Forensic Science International

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This review summarizes the advancement in operational modes and selected applications of the title technique over the past five years. Regarding operational modes particular emphasis is put upon increasing selectivity and resolution, hyphenation of capillary electrophoresis with techniques based on other than electromigration principles, the so-called chip technology and new ways of detection. In applications selected examples of chiral separations and separation of biopolymers (proteins, nucleic acids) are emphasized. It is demonstrated that capillary electrophoresis represents a complementary technique to high-performance column chromatography and in a number of cases it offers better separations than standard chromatographic procedures.

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Gradient elution for micellar electrokinetic capillary chromatography

Cited by 136 publications

References 17 publications

Compositional effects on electrophoretic and chromatographic figures of merit in electrokinetic chromatography with cetyltrimethylammonium bromide/sodium octyl sulfate vesicles as the pseudostationary phase. Part 1: Effect of the phase ratio

Compositional effects on electrophoretic and chromatographic figures of merit in electrokinetic chromatography with cetyltrimethylammonium bromide/sodium octyl sulfate vesicles as the pseudostationary phase. Part 1: Effect of the phase ratio

Parameters controlling the elution window and retention factors in micellar electrokinetic capillary chromatography

Advances in capillary electrophoresis

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