References of "Servais, Anne-Catherine"
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See detailEnantiomeric separation of basic compounds usin heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin in combination with potassium camphorsulfonate in nonaqueous capillary electrophoresis: Optimization by means of an experimental design
Servais, Anne-Catherine ULg; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Electrophoresis (2004), 25(16), 2701-2710

The enantiomeric separation of a series of basic pharmaceuticals (beta-blockers, local anesthetics, sympathomimetics) has been investigated in nonaqueous capillary electrophoresis (NACE) systems using ... [more ▼]

The enantiomeric separation of a series of basic pharmaceuticals (beta-blockers, local anesthetics, sympathomimetics) has been investigated in nonaqueous capillary electrophoresis (NACE) systems using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-P-CD) in combination with potassium camphorsulfonate (camphorSO(3)(-)). For this purpose, a face-centered central composite design with 11 experimental points was applied. The effect of the concentrations of HDMS-beta-CD and camphorSO(3)(-) on enantioresolution was statistically evaluated and depended largely on the considered analyte. The presence of camphorSO(3)(-) was found to be particularly useful for the enantioseparation of compounds with high affinity for the anionic CD. CamphorSO(3)(-) seems to act as a competitor, reducing the affinity for the CD, probably by ion-pair formation with these analytes. For compounds with lower affinity for HDMS-beta-CD, the combination of camphorSO(3)(-) and the CD appeared to have a favorable effect on enantioresolution only if the optimal CD concentration could be reached. On the other hand, for compounds characterized by a very low affinity for the anionic CD, the association of camphorSO(3)(-) and HDMS-beta-CD is always unfavorable. Finally, experimental conditions were selected by means of the multivariate approach in order to obtain the highest resolution (R-s) value for each studied compound. [less ▲]

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See detailDetermination of salbutamol enantiomers in human urine using heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-cyclodextrin in nonaqueous capillary electrophoresis
Servais, Anne-Catherine ULg; Chiap, Patrice ULg; Hubert, Philippe ULg et al

in Electrophoresis (2004), 25(10-11), 1632-1640

Nonaqueous capillary electrophoresis (NACE) was successfully applied to the resolution and the determination of salbutamol enantiomers in urine samples using heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta ... [more ▼]

Nonaqueous capillary electrophoresis (NACE) was successfully applied to the resolution and the determination of salbutamol enantiomers in urine samples using heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-cyclodextrin (HDAS-beta-CD). After optimization of the electrophoretic parameters, namely the background electrolyte (BGE) composition and the HDAS-beta-CD concentration, salbutamol enantiomers were completely resolved using a BGE made up of 10 mm ammonium formate and 15 mm HDAS-beta-CD in methanol acidified with 0.75 M formic acid. Isoprenaline was selected as internal standard. Solid-phase extraction (SPE) was used for sample cleanup prior to the CE separation. Different sorbents involving polar, nonpolar interactions or dual retention mechanisms were evaluated and extraction cartridges containing both nonpolar and strong cation-exchange functionalities were finally selected. Salbutamol enantiomers recoveries from urine samples were determined. The method was then successfully validated using a new approach based on accuracy profiles over a concentration range from 375 to 7500 ng/mL for each enantiomer. [less ▲]

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See detailEffects of background electrolyte composition and addition of selectors on separation selectivity in nonaqueous capillary electrophoresis
Fillet, Marianne ULg; Servais, Anne-Catherine ULg; Crommen, Jacques ULg

in Electrophoresis (2003), 24(10), 1499-1507

This review gives a survey of the approaches employed to obtain, enhance and tune selectivity in nonaqueous capillary electrophoresis (NACE). Recent developments in NACE are described and the effects of ... [more ▼]

This review gives a survey of the approaches employed to obtain, enhance and tune selectivity in nonaqueous capillary electrophoresis (NACE). Recent developments in NACE are described and the effects of background electrolyte composition and addition of selectors on separation selectivity are discussed. The use of one organic solvent, a mixture of several organic solvents or the use of additives to tune separation selectivity in NACE is presented and a list of relevant applications is included. [less ▲]

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See detailSynergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis
Servais, Anne-Catherine ULg; Fillet, Marianne ULg; Abushoffa, Adel M. et al

in Electrophoresis (2003), 24(3), 363-369

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with ... [more ▼]

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with cyclodextrins (CDs). The simultaneous addition to the methanolic background electrolyte (BGE) of (+)-S-camphorsulfonate or alkanesulfonates and an anionic beta-cyclodextrin derivative, heptakis(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-beta-CD), led to partial or complete enantioresolution in most cases. In the absence of ion-pairing reagent, the enantiomeric resolution obtained with this CD derivative was most often completely lost or strongly reduced, indicating the important role of ion-pairing in the chiral recognition mechanism in these NACE systems. The influence of the nature and concentration of the counterion and the anionic CD derivative on the enantioseparation of basic compounds was studied. Synergistic effects between these two kinds of charged additives were clearly observed. [less ▲]

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See detailEnhancement of selectivity and resolution in the enantioseparation of uncharged compounds using mixtures of oppositely charged cyclodextrins in capillary electrophoresis.
Abushoffa, Adel M; Fillet, Marianne ULg; Servais, Anne-Catherine ULg et al

in Electrophoresis (2003), 24(3), 343-50

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 ... [more ▼]

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-beta-CD (PMMAbetaCD) and the single-isomer polyanionic CD, heptakis-6-sulfato-beta-cyclodextrin (HSbetaCD) 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. [less ▲]

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See detailOptimization of the separation of beta-blockers by ion-pair capillary electrophoresis in non-aqueous media using univariate and multivariate approaches
Servais, Anne-Catherine ULg; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal of Separation Science (2002), 25(15-17), 1087-1095

The separation of four beta-blocking drug substances (atenolol, sotalol, betaxolol, and metoprolol) selected as model basic analytes has been investigated in non-aqueous capillary electrophoresis (NACE ... [more ▼]

The separation of four beta-blocking drug substances (atenolol, sotalol, betaxolol, and metoprolol) selected as model basic analytes has been investigated in non-aqueous capillary electrophoresis (NACE) using the principle of ion-pair formation. Camphorsulphonate was selected as the counter-ion in a background electrolyte (BGE) made up of formate buffer in a mixture of acetonitrile/methanol or acetonitrile/ethanol. The influence on resolution of the concentration of the counter-ion, the nature and proportion of the organic solvents, as well as the concentration of the ionic components of the BGE was first studied by a univariate approach. An experimental design was then applied to estimate possible quadratic effects and first-order interactions. To identify the most important factors affecting the separation of the four beta-blockers, a two-level fractional factorial design with 16 experimental points was applied as a screening test. A three factor Box-Behnken design with 12 experimental points was used to predict and optimize the selectivity. Finally the optimal conditions obtained by the univariate and the multivariate, approaches were compared. [less ▲]

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