Use of charged and neutral cyclodextrins in capillary zone electrophoresis: enantiomeric resolution of some 2-hydroxy acids (original) (raw)
Related papers
Electrophoresis, 1995
Further study on the use of uncharged P-cyclodextrin polymer in capillary electrophoresis: Enantiomeric separation of some a-hydroxy acids Uncharged fi-cyclodextrin polymer was used as chiral selector for the enantiomeric separation of some a-hydroxy acids by capillary electrophoresis. Complexation and enantiomeric resolution of mandelic acid, m-hydroxy and p-hydroxymandelic acid, 3,4-dihydroxymandelic acid, as well as 2-and 3-phenyllactic acid were studied, changing the concentration of the B-cyclodextrin polymer added to the background electrolyte at different pH in the range of 4.5-7. Furthermore, the effects of the concentration of the background electrolyte, column temperature, and applied voltage on chiral resolution were also examined. The best enantiomeric separations were obtained using a background electrolyte at pH 6 containing 100 mg/mL of fbcyclodextrin polymer.
Chromatographia, 1996
13-cyclodextrin derivatives, namely 6 A methylamino-13-CD and hepta-methylamino-J3-CD have been used as chiral selectors for the enantiomeric separation of a number of acidic and basic compounds by capillary electrophoresis employing either coated or uncoated capillaries. The effects of the CD type and concentration and the pH of the background electrolyte on the mobility and chiral resolution of the analytes have been studied. The use of monomethylamino-13-CD in a coated capillary allowed the enantiomeric resolution of phenyl lactic acid, warfarin and acenocoumarol but was not successful for tiaprofen and its 3-isomer. The heptamethyl~ amino derivative, under the same experimental conditions, was a better chiral selector than the monosubstituted CD toward the arylpropionic acids and phenyl lactic acid while the anticoagulant drugs showed poor or no chiral resolution. Inversion of migration order was obtained for phenyl lactic acid, warfarin and acenocoumarol enantiomers. The enantiomers of basic compounds of pharmaceutical interest, namely propranolol, terbutaline, ketamine, chlorpheniramine and isoproterenol were only resolved using monomethylamino-~-CD dissolved in a phosphate buffer containing tetramethylammonium ions.
Use of cationic cyclodextrin for enantioseparation by capillary electrophoresis
Journal of Chromatography A, 1998
The usability of 2-hydroxy-3-trimethylammoniopropyl-β-cyclodextrin for chiral discrimination of various basic and acidic substances is described. The dependence of chiral separation on cyclodextrin (CD) concentration and pH value was investigated. Altering the pH value the migration order of the enantiomers of acidic analytes could be changed. Due to the quaternary ammonium structure of the CD molecule, a reversal of the electroosmotic
ELECTROPHORESIS, 2003
The enantiomeric separation of some nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated in capillary electrophoresis (CE) using dual systems with mixtures of charged cyclodextrin (CD) derivatives. A significant enhancement of selectivity and resolution could be achieved in the enantioseparation of these analytes in their uncharged form by the simultaneous addition of two oppositely charged CD derivatives to the background electrolyte. The combination of the single-isomer cationic CD, permethyl-6-monoamino-6-monodeoxy-b-CD (PMMAbCD) and the single-isomer polyanionic CD, heptakis-6-sulfato-b-cyclodextrin (HSbCD) in a pH 2.5 phosphoric acid-triethanolamine buffer, was designed and employed for the enantioseparation of profens. The improvement in selectivity and resolution can be attributed to the fact that the two CDs, which lead to independent and enantioselective complexation with the analyte enantiomers, have not only opposite effects on the electrophoretic mobility of these compounds but also opposite affinity patterns towards the enantiomers of these compounds. Binding constants for these enantiomers with each CD were determined using linear regression approach, in order to be able to predict the effect of the concentrations of the two CDs on enantiomeric selectivity and resolution in such dual systems.
Use of cyclodextrins in capillary zone electrophoresis
Journal of Chromatography A, 1991
Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol. Both uncoated and polyacrylamide-coated capillaries were tested for method optimization using either negatively charged or native cyclodextrins (CD) added to the background electrolyte (BGE). The resolution was strongly influenced by the CD type and concentration as well as by the pH and the concentration of the BGE. Among the CDs tested, carboxymethylated-P-cyclodextrin allowed the baseline separation of tramadol enantiomers. After the method was optimized, it was validated in a coated capillary for enantiomeric analysis of tramadol enantiomers in pharmaceutical formulation, including specificity and elution order, linearity, accuracy and precision, determination of limit of detection (LOD) and quantification (LOQ), enantiomeric purity linearity, freedom from interference, and stability of sample solutions. Precision at the target concentration was less than 2%, with an accuracy higher than 99%. Furthermore, the method was able to detect 0.3% and to quantify 1% of the minor enantiomer in the presence of the major one at the target value.
Use of cyclodextrins in capillary electrophoresis
1993
Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol. Both uncoated and polyacrylamide-coated capillaries were tested for method optimization using either negatively charged or native cyclodextrins (CD) added to the background electrolyte (BGE). The resolution was strongly influenced by the CD type and concentration as well as by the pH and the concentration of the BGE. Among the CDs tested, carboxymethylated-P-cyclodextrin allowed the baseline separation of tramadol enantiomers. After the method was optimized, it was validated in a coated capillary for enantiomeric analysis of tramadol enantiomers in pharmaceutical formulation, including specificity and elution order, linearity, accuracy and precision, determination of limit of detection (LOD) and quantification (LOQ), enantiomeric purity linearity, freedom from interference, and stability of sample solutions. Precision at the target concentration was less than 2%, with an accuracy higher than 99%. Furthermore, the method was able to detect 0.3% and to quantify 1% of the minor enantiomer in the presence of the major one at the target value.
Electrophoresis, 1997
Capillary electrophoretic separations of enantiomers using cyclodextrin-containing background electrolytes The 1996 primary literature papers which deal with the separation of enantiomers using cyclodextrins are reviewed here. Though the majority of the papers still use the neutral native cyclodextrins or the neutral derivatized cyclodextrins as resolving agents, there was a significant increase in number of separations which relied on charged cyclodextrins, both weak electrolytes and strong electrolytes, as resolving agents. Also, there was an increase in the number of papers which reported binding constants and correlated them with other physical or chemical characteristics of the analytes. Several successful minor enantiomer determinations were presented, pushing the reliable quantitation levels below 0.1%. Work continued on the simultaneous use of neutral and charged cyclodextrins to improve separation selectivity or peak resolution.
Analytical Chemistry, 1994
The volume of literature on chiral separations by capillary electrophoresis (CE) grew very rapidly over the last three years, culminating in a couple of recent, comprehensive reviews.lg2 Cyclodextrins, including native CY-,^^ @-,3-10 and y-c y c l~d e x t r i n s ,~~~~~J~ 2,6-dimethyl-and 2,3,6-trimethyl-@c y~l o d e x t r i n s ,~~~*~-~ 1~1 2 and hydroxyethyl-l3 and hydroxypropyl-@-cyclodextrins, 13-20 have been the most commonly used chiral resolving agents. Several authors recognized that the extent f Dedicated to Professor JBnos Inczbdy on the occasion of his 70th birthday.
Analytica Chimica Acta, 2006
The chiral resolving ability of a novel single-isomer cationic -cyclodextrin (CD), mono-6 A-propylammonium-6 A-deoxy--cyclodextrin chloride (PrAMCD), as a chiral selector in capillary electrophoresis (CE) is reported in this work for the enantioseparation of hydroxy, carboxylic acids and amphoteric analytes. The effect of chiral selector concentration on the resolution was studied. Good resolutions were achieved for hydroxy acids. Optimum resolutions were obtained even at 3.5 mM CD concentration for carboxylic acids. The electrophoretic method showed good linearity and reproducibility in terms of migration times and peak areas, which should make it suitable for routine analysis. In addition, baseline chiral separation of a six-acid mixture was achieved within 20 min. PrAMCD proved to be an effective chiral selector for acidic analytes.
Analytical Chemistry, 1994
The volume of literature on chiral separations by capillary electrophoresis (CE) grew very rapidly over the last three years, culminating in a couple of recent, comprehensive reviews.lg2 Cyclodextrins, including native CY-,^^ @-,3-10 and y-c y c l~d e x t r i n s ,~~~~~J~ 2,6-dimethyl-and 2,3,6-trimethyl-@c y~l o d e x t r i n s ,~~~*~-~ 1~1 2 and hydroxyethyl-l3 and hydroxypropyl-@-cyclodextrins, 13-20 have been the most commonly used chiral resolving agents. Several authors recognized that the extent f Dedicated to Professor JBnos Inczbdy on the occasion of his 70th birthday.