Separation selectivity in chiral and achiral capillary electrophoresis with mixed cyclodextrins

Lurie, Ira S.

doi:10.1016/s0021-9673(97)00700-0

Cited by 107 publications

(60 citation statements)

References 19 publications

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“…It was shown that the combination of neutral native with synthetic neutral or charged CD derivatives often significantly enhances resolution . Since specialized reviews deal with the use of dual CD systems, this topic will not be discussed here in detail [461,462]. Another approach reported is the combination of CDs with chiral surfactants such as bile salts [463][464][465], decanoyl-N-methyl glucanoid [466] and poly (sodium-N-undecenyl-dvalinate) [467].…”

Section: Non-aqueous Ce (Nace)mentioning

confidence: 99%

Chiral separation by chromatographic and electromigration techniques. A Review

Gübitz

Schmid

2001

Biopharm & Drug Disp

225

135

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This review gives a survey of different chiral separation principles and their use in high-performance liquid chromatography (HPLC), gas chromatography (GC), supercritical fluid chromatography (SFC), thin-layer chromatography (TLC), capillary electrophoresis (CE) and capillary electrochromatography (CEC) highlighting new developments and innovative techniques. The mechanisms of the different separation principles are briefly discussed and some selected applications are shown.

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Section: Non-aqueous Ce (Nace)mentioning

confidence: 99%

Chiral separation by chromatographic and electromigration techniques. A Review

Gübitz

Schmid

2001

Biopharm & Drug Disp

225

135

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“…On the other hand, the addition of b-CD did not improve the chiral separation of PCBs as in the case of Succ-b-CD. The results obtained with both CDs Succ-b-CD and b-CD-NH 2 show that when a charged CD derivative acts as chiral selector it is not useful to add a second CD to work also as chiral selector, probably due to a competitive effect of both CDs as chiral selectors [44].…”

Section: Discussionmentioning

confidence: 97%

“…Thus, the use of acetonitrile, methanol or isopropanol in the buffer solution showed that only the use of 10% acetonitrile enabled the partial chiral separation (R s 0.4) of two PCBs as it can be seen in Table 2. Finally, mixtures of Succ-b-CD/b-CD were used but the results showed that any PCB was enantiomerically separated, which could be probably due to a competitive effect of both CDs by the PCB because both CDs act as chiral selectors for PCBs [44].…”

Section: Enantiomeric Separation Of Chiral Pcbs Using Anionic Cds As mentioning

confidence: 99%

Comparison of charged cyclodextrin derivatives for the chiral separation of atropisomeric polychlorinated biphenyls by capillary electrophoresis

2003

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Comparison of charged cyclodextrin derivatives for the chiral separation of atropisomeric polychlorinated biphenyls by capillary electrophoresisCharged cyclodextrin (CD) derivatives were used as chiral selectors in electrokinetic chromatography (EKC) for the chiral separation of highly hydrophobic neutral racemates such as atropisomeric polychlorinated biphenyls (PCBs). b-CD-phosphated, b-CD sulfated, succinylated-g-CD (Succ-g-CD) and succinylated-b-CD (Succ-b-CD) were used as anionic CDs. As cationic CD, 6-monodeoxy-6-monoamino-b-CD (b-CD-NH 2 ) was tested for the first time in order to separate PCBs. From the different CD derivatives employed, the best separations were obtained with the cationic CD derivative. Thus, the use of b-CD-NH 2 in phosphate buffer at pH 2.0 containing urea allowed the chiral recognition of eleven PCBs (45, 84, 88, 91, 95, 131, 136, 144, 149, 176, and 197). In this case, the addition of 2 M urea to the buffer solution was crucial to achieve the chiral separation of PCBs. The addition of acetonitrile to 10 mM phosphate buffer (pH 2.0) with 30 mM b-CD-NH 2 and 2 M urea improved considerably the chiral resolution obtained for PCBs 91, 95, 136, 144, 149, and 197 although an increase in the analysis time was also observed. All the results obtained were compared with those previously obtained with the dual CD system carboxymethyl-g-CD/b-CD.

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“…The chiral selector is forming labile diastereoisomers with analytes during the electrophoretic run. Major chiral selectors currently used in CE include neutral and charged cyclodextrins and their derivatives [1][2][3], crown ethers [4], chiral imprinted polymers [5], enantioselective metal complexes [6], chiral surfactants [7], proteins [8], polysaccharides [9], chiral ion-pairing reagents [10] and macrocyclic antibiotics .…”

Section: Introductionmentioning

confidence: 99%

Enantioseparation in CE using macrocyclic antibiotics as chiral selectors

Hui¹,

Caude²

1999

Analusis

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Micellar phaseA mixed micelle system is obtained by adding surfactants such as SDS (sodium dodecylsulfate) above its critical micelle concentration (CMC) to the run buffers containing antibiotics. To date, only the glycopeptide antibiotics have been used in conjunction with micelles. In the case of vancomycin, it is estimated that approximately 90 % of vancomycin is bound to the SDS micelle. Thus there are three pseudophases: the free vancomycin, the vancomycin-SDS mixed micelle and the bulk aqueous solution. The use of such mixed micelle systems allow the resolution a variety of hydrophobic, neutral analytes, e.g., pesticides and drugs [16]. The major separation mechanism is thought to be the partitioning of hydrophobic, neutral compounds between the three pseudophases. In a recent study, Rundlett and Armstrong [17] found the addition of SDS micelles with vancomycin to the run buffer can reverse the elution order of enantiomers, decreases analysis times and enhances efficiencies by one order of magnitude.The addition of SDS to a teicoplanin-based separation produces similar effects to vancomycin experiments [17,22]. However, the elution order of enantiomers in teicoplanin system is not universal. In the case of ristocetin A, the addition of SDS to the analogous conditions does not produce the extensive increase in efficiency and decrease in migration times. Furthermore, there is a significant concentrationdependent effect on selectivity and the reversal of elution order is uncommon [21]. Complementarity among glycopeptide antibiotics used as chiral selectorsAlthough all of three glycopeptide antibiotics vancomycin, teicoplanin and ristocetin A belong to the same family, they have some distinct structural differences as well. Therefore, they exhibit somewhat similar but not identical enantioselectivities. In fact, the glycopeptide antibiotics are complementary to one another. Armstrong et al. proposed that if only a partial enantioresolution can be obtained with one glycopeptide, there is a high probability that a baseline or better separation may be obtained with another glycopeptide [30]. This "principle of complementary separations" is illustrated in figure 3. While it is not yet possible to predict which glycopeptide antibiotic will provide the best resolution for a given analyte, it appears that a partial resolution with one selector usually can be improved upon by using one of the structurally related macrocyclic glycopeptide chiral selectors. ApplicationsGenerally, rifamycin B is chosen to separate cationic compounds [12,26], while the glycopeptide antibiotics vancomycin, teicoplanin and ristocetin A are used for the separation of compounds containing an anionic moiety such as carboxylate, phosphate, sulphonate groups, etc. Approximately 500 racemic analytes have been electrophoretically resolved with glycopeptide antibiotics, including most N-blocked amino acids, numerous nonsteroidal antiinflammatory compounds, antineoplasics, lactic acids, herbicides, rodenticides and a variety of pharmaceutically im...

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Separation selectivity in chiral and achiral capillary electrophoresis with mixed cyclodextrins

Cited by 107 publications

References 19 publications

Chiral separation by chromatographic and electromigration techniques. A Review

Chiral separation by chromatographic and electromigration techniques. A Review

Comparison of charged cyclodextrin derivatives for the chiral separation of atropisomeric polychlorinated biphenyls by capillary electrophoresis

Enantioseparation in CE using macrocyclic antibiotics as chiral selectors

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