Comparative studies on the enantioseparation of hydrobenzoin and structurally related compounds by capillary zone electrophoresis with sulfated β-cyclodextrin as the chiral selector in the presence and absence of borate complexation

Lin, Shinn-Kuang; Lin, Chin‐Feng

doi:10.1016/j.chroma.2003.11.100

Cited by 15 publications

(1 citation statement)

References 25 publications

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“…It is well-known that enantioseparation of neutral analytes cannot be achieved by neutral CD unless the buffer system can form charged complexes with analytes. 18 In the study of the complexation between buffer and analytes, the complexation phenomenon of borate buffer and vicinal hydroxyl of analytes has been extensively studied. 19 In our study, a new CZE method has been developed to separate the 2,3-dihydroxy-3-phenylpropionate enantiomers, such as methyl-2,3-dihydroxy-3-phenylpropionate, ethyl-2,3-dihydroxy-3-phenylpropionate, and isopropyl-2,3-dihydroxy-3-phenylpropionate with neutral hydroxypropyl (HP) -b-CD as a chiral selector in borate buffer.…”

Section: Introductionmentioning

confidence: 99%

Determination of enantiomeric excess for 2,3‐dihydroxy‐3‐phenylpropionate compounds by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin as chiral selector

Zhao¹,

Yang²,

Wang³

et al. 2007

Chirality

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A new capillary zone electrophoresis (CZE) method was developed to separate three chiral 2,3-dihydroxy-3-phenylpropionate enantiomers using neutral hydroxypropyl-beta-CD (HP-beta-CD) as chiral selector and borate as background electrolyte. The results showed that HP-beta-CD exhibited good enantioselectivity and high resolution was achieved under the optimum condition of pH 10.3, 200 mM borate buffer containing 6% methanol and 50 mM HP-beta-CD at 15 kV and 20 degrees C within 16 min. The precision of the method was <0.9% for migration time and 4.5% for corrected peak area. In addition, the developed method was successfully applied to the determination of enantiomeric excess (ee) of synthetic 2,3-dihydroxy-3-phenylpropionate samples. With this method, low as 0.2% impurity of the undesirable enantiomer in the presence of high amount of target enantiomer was determined. The results demonstrated that the proposed CZE method is a simple and useful technique and is applicable to ee assay of 2,3-dihydroxy-3-phenylpropionate enantiomers.

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Section: Introductionmentioning

confidence: 99%

Determination of enantiomeric excess for 2,3‐dihydroxy‐3‐phenylpropionate compounds by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin as chiral selector

Zhao¹,

Yang²,

Wang³

et al. 2007

Chirality

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Enantioseparations of hydrobenzoin and structurally related compounds in capillary zone electrophoresis using heptakis(2,3‐dihydroxy‐6‐O‐sulfo)‐β‐cyclodextrin as chiral selector and enantiomer migration reversal of hydrobenzoin with a dual cyclodextrin system in the presence of borate complexation

Lin

Fang

et al. 2004

Electrophoresis

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We investigated the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary electrophoresis (CE) using the single-isomer heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin (SI-S-beta-CD) as a chiral selector in the presence and absence of borate complexation and enantiomer migration reversal of hydrobenzoin with a dual CD system consisting of SI-S-beta-CD and beta-CD in the presence of borate complexation at pH 9.0 in a borate buffer. The enantioselectivity of hydrobenzoin increased remarkably with increasing SI-S-beta-CD concentration and the enantioseparation depended on CD complexation between hydrobenzoin-borate and SI-S-beta-CD. The (S,S)-enantiomer of hydrobenzoin-borate complexes interacted more strongly than the (R,R)-enantiomer with SI-S-beta-CD. The enantiomers of hydrobenzoin could be baseline-resolved in the presence of SI-S-beta-CD at a concentration as low as 0.1% w/v, whereas the three test analytes were simultaneously enantioseparated with addition of 0.3% w/v SI-S-beta-CD or at concentrations >2.0% w/v in a borate buffer and 0.5% w/v in a phosphate background electrolyte at pH 9.0. Compared with the results obtained previously using randomly sulfated beta-CD (MI-S-beta-CD) in a borate buffer, enantioseparation of these three benzoin compounds is more advantageously aided by SI-S-beta-CD as the chiral selector. The enantioselectivity of hydrobenzoin depended greatly on the degree of substitution of sulfated beta-CD. Moreover, binding constants of the enantiomers of benzoin compounds to SI-S-beta-CD and those of hydrobenzoin-borate complexes to SI-S-beta-CD were evaluated for a better understanding of the role of CD complexation in the enantioseparation and chiral recognition. Enantiomer migration reversal of hydrobenzoin could be observed by varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. SI-S-beta-CD and beta-CD showed the same chiral recognition pattern but they exhibited opposite effects on the mobility of the enantiomers.

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Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

et al. 2005

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In this study, enantioseparations of five phenothiazines, including promethazine, ethopropazine, trimeprazine, methotrimeprazine, and thioridazine, in CD-modified CZE using dual CD systems consisting of randomly sulfate-substituted CD (MI-S-beta-CD) and a neutral CD as chiral selectors in a citrate buffer (100 mM) at pH 3.0 were investigated. The results indicate that MI-S-beta-CD is an excellent chiral selector for enantioseparation of ethopropazine. The enantiomers of promethazine can also be baseline-resolved with MI-S-beta-CD at concentrations in the range of 0.5-1.0% w/v. On the other hand, thioridazine and trimeprazine interact strongly with neutral CDs. As a result, the enantioselectivity of these two phenothiazines is remarkably and synergistically enhanced with increasing the concentration of neutral CDs in the presence of MI-S-beta-CD and simultaneous enantioseparations of these phenothiazines, except for methotrimeprazine, could favorably be achieved with the use of dual CD systems. Moreover, by varying the concentration of beta-CD or gamma-CD at a fixed concentration of MI-S-beta-CD (0.75% w/v) reversal of the enantiomer migration order of promethazine occurred. This may be attributable to the opposite effects of charged and neutral CDs on the mobility of the enantiomers of promethazine.

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Comparative studies on the enantioseparation of hydrobenzoin and structurally related compounds by capillary zone electrophoresis with sulfated β-cyclodextrin as the chiral selector in the presence and absence of borate complexation

Cited by 15 publications

References 25 publications

Determination of enantiomeric excess for 2,3‐dihydroxy‐3‐phenylpropionate compounds by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin as chiral selector

Determination of enantiomeric excess for 2,3‐dihydroxy‐3‐phenylpropionate compounds by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin as chiral selector

Enantioseparation of phenothiazines in cyclodextrin-modified capillary zone electrophoresis using sulfated cyclodextrins as chiral selectors

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