- Clicked AC regioisomer cationic cyclodextrins for enantioseparation
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Novel AC regioisomer cationic cyclodextrins have been successfully prepared with azide/alkyne click chemistry. The clicked CDs were explored for the enantioseparation of acidic racemates in capillary electrophoresis.
- Zhou, Jie,Liu, Yun,Lu, Yingying,Tang, Jian,Tang, Weihua
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p. 54512 - 54516
(2015/02/05)
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- Chiral separation of enantiomers of amino acid derivatives by HPLC on vancomycin and teicoplanin chiral stationary phases
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The chiral separation of α-amino acids by liquid chromatography using macrocyclic antibiotic bonded stationary phases were studied. Teicoplanin and vancomycin bonded stationary phases have been used to separate enantiomers of dansyl amino acids in the reversed - phase high performance liquid chromatography mode. By comparison of chromatographic parameters obtained by use of both chiral stationary phases it the mechanism of chiral separation could be suggested. The better separation - greater value of R(j,i) of enantiomers - was achieved by the teicoplanin column.
- Lehotay, Jozef,Hrobonova,Krupcik,Cizmarik
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p. 863 - 865
(2007/10/03)
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- Effect of micelles and mixed micelles on efficiency and selectivity of antibiotic-based capillary electrophoretic enantioseparations.
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Vancomycin (an oligophenolic, glycopeptide, macrocyclic antibiotic) has been shown to be a superb chiral selector for anionic and neutral compounds. It was found that adding sodium dodecyl sulfate to the run buffer increased efficiency by over 1 order of magnitude, decreased analysis times, and reversed the elution order of the enantiomers. This allows for control of the retention order as well as the resolution of enantiomers in complex mixtures in a single run. A mechanism is proposed which explains all of the observed effects and is verified experimentally. Since vancomycin is present in both the micelle and in free solution, previously proposed micelle-selector models are, at best, limiting cases. A general equation is derived which can be used to describe all possible interactions, including those with the capillary wall, if needed. Also, it is shown that electrophoretic mobilities and not migration times must be used to calculate binding constants of a solute to the micelle, the chiral selector, or both. Furthermore, it is shown that a neutral marker molecule cannot be used to accurately correct mobilities that have been altered due to changes in solution viscosity. While this work utilizes the practical vancomycin-micelle system, the general conclusions and theory apply to most other analogous CE systems as well.
- Rundlett,Armstrong
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p. 2088 - 2095
(2007/10/02)
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