Microemulsion electrokinetic chromatography with different organic modifiers: separation of water- and lipid-soluble vitamins

Boso, R.L.; Bellini, Maria Silvana; Mikšı́k, Ivan; Deyl, Z.

doi:10.1016/0021-9673(95)00163-h

Cited by 90 publications

(45 citation statements)

References 4 publications

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“…Mertzman [50] and Pascoe [51] have also reported the use of low interfacial oils like ethyl acetate in MEEKC separations. A range of other oils have been reported [26,31,35,37,48,52,53] including cyclohexane, chloroform, methylene chloride, amyl alcohol, and butyl chloride. An investigation into the use of low interfacial tension oils in conjunction with a chiral surfactant has also been carried out [50].…”

Section: Oil Phasementioning

confidence: 99%

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Recent advances in the development and application of microemulsion EKC

et al. 2007

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Microemulsion EKC (MEEKC) is an electrodriven separation technique. Separations are typically achieved using oil-in-water microemulsions, which are composed of nanometre-sized oil droplets suspended in an aqueous buffer. The droplets are stabilised by a surfactant and a cosurfactant. The novel use of water-in-oil microemulsions has also been investigated. This review summarises the advances in the development of MEEKC separations and also the different areas of application including determination of log P values, pharmaceutical applications, chiral analysis, natural products and bioanalytical separations and the use of new methods such as multiplexed MEEKC and high speed MEEKC. Recent applications (2004-2006) are tabulated for each area with microemulsion composition details.

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Section: Oil Phasementioning

confidence: 99%

“…The use of cationic surfactants has been used to eliminate ion-pair reactions, which occur between cations and the negatively charged droplets [31,37]. Use of cationic surfactants results in a reversal of the EOF and requires the use of negative polarity voltage.…”

Section: Surfactant Type and Concentrationmentioning

confidence: 99%

Recent advances in the development and application of microemulsion EKC

et al. 2007

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“…Indeed, MEEKC has been recently demonstrated to be highly useful for the separation of a diverse group of highly hydrophobic substances, such as b-diketones [28], polyaromatic hydrocarbons [29], steroids [30], polymer additives [31], fatty acids [32], biphenyl nitrile compounds [33], diphenylhydrazones of dicarbonyl sugars [34], lipid-soluble vitamins [35], and hematoporphyrin mixtures [36]. Note that in order to achieve optimal separation of various hydrophobic compounds, the addition of an organic modifier (i.e., a so-called second cosurfactant, such as 2-proponal) into the running buffer is at times often necessary [25][26][27].…”

Section: Meekcmentioning

confidence: 99%

Investigation of solvent effects in capillary electrophoresis for the separation of biological porphyrin methyl esters

Chang

Huie

2005

Electrophoresis

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The effects of organic solvents on the capillary electrophoresis (CE) separation of a number of important biological porphyrin methyl esters - six weakly basic, hydrophobic cyclic tetrapyrroles possessing two and four to eight methyl ester groups around the periphery of the porphyrin ring - were investigated in the mode of micellar electrokinetic chromatography (MEKC), microemulsion electrokinetic chromatography (MEEKC), and nonaqueous CE. In aqueous MEKC, partial separation of the six neutral porphyrin methyl esters was obtained with an organic modifier (acetonitrile) in the concentration range between 20 and 40%, in which sodium dodecyl sulfate (SDS) molecules might be present in the form of SDS micelles and/or SDS micelle-like aggregates. Relatively stable SDS micelles can be formed in nonaqueous MEKC using formamide as the separation medium, but the separation of the target analytes remained unsatisfactory. Improved resolution of all six porphyrin methyl esters was obtained using MEEKC with the running buffer consisting of 0.8% w/w n-heptane (oil phase), 2.25% w/w SDS and 1.0% w/w Brij 35 (mixed surfactant), 6.6% w/w 1-butanol (cosurfactant), and 30% v/v 2-propanol (second cosurfactant), but reproducibility in terms of peak areas for certain porphyrins (especially uroporphyrin I octamethyl ester) was found to be very poor. Best separation performances were achieved with nonaqueous CE separations in which the weakly basic porphyrin methyl esters were protonated under strongly acidic conditions (e.g., using 10 mM perchloric acid) in mixed organic solvents. For example, using a 50:50 mixture of methanol and acetonitrile as the separation medium, baseline separation of all six (positively charged) porphyrin methyl esters can be obtained within 3 min and the average precision (RSD, N = 13) in terms of migration time and peak area were 0.55 and 2.16%, respectively.

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“…After the first report on the use of a microemulsion as a running buffer in CE, an increasing number of papers describing different applications of microemulsion electrokinetic chromatography (MEEKC) were published. MEEKC has been shown to be useful for the separation of very lipophilic substances such as polyaromatic hydrocarbons (Watarai, 1991;Altria, 2000) and fat-soluble vitamins (Altria, 1999;PedersenBjergaard et al, 2000), and very hydrophilic substances like water-soluble vitamins (Boso et al, 1995;Altria, 1999) and proteins (Zhou et al, 1999), as well as pharmaceuticals (Terabe et al, 1992;Altria, 1999) and natural products (Debusschère et al, 1997;Li et al, 1998).…”

Section: Introductionmentioning

confidence: 98%

Microemulsion electrokinetic chromatography with laser‐induced ﬂuorescence detection: as tested with amino acid derivatives

Xie¹,

Zhang²,

Liu³

et al. 2004

Biomedical Chromatography

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Over a decade ago, microemulsion electrokinetic chromatography was introduced as a novel mode of capillary electrophoresis. However, there has not been publication on the combination of microemulsion electrokinetic chromatography with laser-induced fluorescence detection. In this paper, a preliminary method using microemulsion eletrokinetic chromatography combined with laser-induced fluorescence detection and second derivative electrophoregram was established as a sensitive and selective assay for separation and determination of nine amino acids after derivatization with 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazol. The derivatization and separation conditions were optimized. In the investigated concentration ranges correlation coefficients were better than 0.995. The relative standard deviation (n = 5) of the migration times and peak heights were 0.56-0.76 and 2.21-7.15%, respectively. The detection limits (S/N = 3) were at a neaomolar level (0.32-2.20 nM). The method was applied for the analysis of compound amino acid injection and a Chinese traditional herbal medicine. The recoveries were 95.9-107.9%.

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Microemulsion electrokinetic chromatography with different organic modifiers: separation of water- and lipid-soluble vitamins

Cited by 90 publications

References 4 publications

Recent advances in the development and application of microemulsion EKC

Recent advances in the development and application of microemulsion EKC

Investigation of solvent effects in capillary electrophoresis for the separation of biological porphyrin methyl esters

Microemulsion electrokinetic chromatography with laser‐induced ﬂuorescence detection: as tested with amino acid derivatives

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