Microemulsion electrokinetic chromatography – or solvent-modified micellar electrokinetic chromatography?

Hansen, Steen Honoré; Gabel-Jensen, Charlotte; El-Sherbiny, Dina T.; Pedersen‐Bjergaard, Stig

doi:10.1016/s0165-9936(01)00127-3

Cited by 74 publications

(74 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although MEEKC separation efficiency is often reported, and in several direct comparisons with MEKC it was more frequently observed to be higher [28,39,58] rather than lower [40], zone broadening in MEEKC has received little if any attention from a fundamental perspective, in contrast to several carefully-conducted efficiency studies in micellar EKC [59][60][61][62][63][64][65][66]. The latter studies along with well-known results for CZE facilitate our synopsis below of relevant zone broadening processes for EKC, prior to the discussion of our chiral MEEKC efficiency results.…”

Section: Efficiency: Results and Trends With Diethyl Tartrate Microemmentioning

confidence: 99%

Two‐chiral component microemulsion EKC – chiral surfactant and chiral oil. Part 2: Diethyl tartrate

Kahle

Foley

2007

Electrophoresis

View full text Add to dashboard Cite

In this second study on dual-chirality microemulsions containing a chiral surfactant and a chiral oil, a less hydrophobic and lower interfacial tension chiral oil, diethyl tartrate, is employed (Part 1, Foley, J. P. et al.., Electrophoresis, DOI: 10.1002/elps.200600551). Six stereochemical combinations of dodecoxycarbonylvaline (DDCV: R, S, or racemic, 2.00% w/v), racemic 2-hexanol (1.65% v/v), and diethyl tartrate (D, L, or racemic, 0.88% v/v) were examined as pseudostationary phases (PSPs) for the enantioseparation of six chiral pharmaceutical compounds: pseudoephedrine, ephedrine, N-methyl ephedrine, metoprolol, synephrine, and atenolol. Average efficiencies increased with the addition of a chiral oil to R-DDCV PSP formulations. Modest improvements in resolution and enantioselectivity (alpha(enant)) were achieved with two-chiral-component systems over the one-chiral-component microemulsion. Slight enantioselective synergies were confirmed using a thermodynamic model. Results obtained in this study are compared to those obtained in Part 1 as well as those obtained with chiral MEEKC using an achiral, low-interfacial-tension oil (ethyl acetate). Dual-chirality microemulsions with the more hydrophobic oil dibutyl tartrate yielded, relative to diethyl tartrate, higher efficiencies (100,000-134,000 vs. 80,800-94,300), but lower resolution (1.64-1.91 vs. 2.08-2.21) due to lower enantioselectivities (1.060-1.067 vs. 1.078-1.081). Atenolol enantiomers could not be separated with the dibutyl tartrate-based microemulsions but were partially resolved using diethyl tartrate microemulsions. A comparable single-chirality microemulsion based on the achiral oil ethyl acetate yielded, relative to diethyl tartrate, lower efficiency (78 300 vs. 91 600), higher resolution (1.99 vs. 1.83), and similar enantioselectivities.

show abstract

Section: Efficiency: Results and Trends With Diethyl Tartrate Microemmentioning

confidence: 99%

Two‐chiral component microemulsion EKC – chiral surfactant and chiral oil. Part 2: Diethyl tartrate

Kahle

Foley

2007

Electrophoresis

View full text Add to dashboard Cite

show abstract

“…In MEKC, surfactant molecules group to form micelles and solutes chromatographically interact with these micelles which facilitates separation [13]. Solutes can penetrate the surface of the MEEKC droplet more easily than the more rigid MEKC micelle [16], which allows MEEKC to be applied to a wider range of solutes. MEEKC has often been found to provide superior separation efficiency to MEKC, probably due to improved mass transfer between the microemulsion droplet and aqueous phase, mediated by the cosurfactant [16].…”

Section: Comparison With Other Capillary Electrophoretic Modesmentioning

confidence: 99%

“…Solutes can penetrate the surface of the MEEKC droplet more easily than the more rigid MEKC micelle [16], which allows MEEKC to be applied to a wider range of solutes. MEEKC has often been found to provide superior separation efficiency to MEKC, probably due to improved mass transfer between the microemulsion droplet and aqueous phase, mediated by the cosurfactant [16]. MEEKC offers a larger separation window, and the size of this window can be controlled [16][17][18], and therefore potentially offers greater separation capability for water-insoluble compounds than MEKC [19].…”

Section: Comparison With Other Capillary Electrophoretic Modesmentioning

confidence: 99%

“…MEEKC has often been found to provide superior separation efficiency to MEKC, probably due to improved mass transfer between the microemulsion droplet and aqueous phase, mediated by the cosurfactant [16]. MEEKC offers a larger separation window, and the size of this window can be controlled [16][17][18], and therefore potentially offers greater separation capability for water-insoluble compounds than MEKC [19]. Investigations have been performed [14] comparing MEEKC to solvent-modified MEKC, which used an electrolyte containing the same buffer, cosurfactant, and amount of SDS as the microemulsion.…”

Section: Comparison With Other Capillary Electrophoretic Modesmentioning

confidence: 99%

See 1 more Smart Citation

Recent advances in microemulsion electrokinetic chromatography

et al. 2004

View full text Add to dashboard Cite

Microemulsion electrokinetic chromatography (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil-in-water microemulsions, which are composed of nanometre-sized droplets of oil suspended in aqueous buffer. The oil droplets are coated in surfactant molecules and the system is stabilised by the addition of a short-chain alcohol cosurfactant. The novel use of water-in-oil microemulsions for MEEKC separations has also been investigated recently. This report summarises the different microemulsion types and compositions used to-date and their applications with a focus on recent papers (2002-2004). The effects of key operating variables (pH, surfactant, cosurfactant, oil phase, buffer, additives, temperature, organic modifier) and methodology techniques are described.

show abstract

“…As a consequence, microemulsions usually only exist in very sharp concentration domains. Strategies for optimisation and selectivity improvement in MEEKC are well documented [41][42][43][44]. The majority of published applications have involved a microemulsion system consisting of octane/1-butanol/ SDS/borate buffer, pH 9.2 [8,23,45].…”

Section: Optimisation Of the Meekc Separation Of Uv-absorbing Componementioning

confidence: 99%

A comparative study of microemulsion electrokinetic capillary chromatography and micellar electrokinetic capillary chromatography for the analysis of UV‐absorbing compounds in human urine

Melin

Perrett

2004

Electrophoresis

View full text Add to dashboard Cite

Separations of human urine by microemulsion electrokinetic chromatography (MEEKC) and micellar electrokinetic capillary chromatography (MEKC) with respect to resolution, migration times and efficiencies were optimized and compared. The optimised MEEKC and MEKC methods were simple and fast, both of which are excellent characteristics for the complex separations required in clinical and biomedical studies. However, resolution in MEKC was significantly greater than in MEEKC although migration times were 30% faster for the optimised MEEKC method. In addition, a faster analysis method (short-end injection) specifically for routine screening purposes was also investigated. With both MEEKC and MEKC modes, this provided short separations (less than 4 min for urine) with no major compromise in resolution. In conclusion, we found that MEEKC offered no real advantage over MEKC for urine analysis.

show abstract

Microemulsion electrokinetic chromatography – or solvent-modified micellar electrokinetic chromatography?

Cited by 74 publications

References 31 publications

Two‐chiral component microemulsion EKC – chiral surfactant and chiral oil. Part 2: Diethyl tartrate

Two‐chiral component microemulsion EKC – chiral surfactant and chiral oil. Part 2: Diethyl tartrate

Recent advances in microemulsion electrokinetic chromatography

A comparative study of microemulsion electrokinetic capillary chromatography and micellar electrokinetic capillary chromatography for the analysis of UV‐absorbing compounds in human urine

Contact Info

Product

Resources

About