Evaluation of a Vancomycin Chiral Stationary Phase in Capillary Electrochromatography Using Polar Organic and Reversed-Phase Modes

Karlsson, Charlotte; Karlsson, Lars; Armstrong, Daniel W.; Owens, Paul K.

doi:10.1021/ac0002792

Cited by 98 publications

(59 citation statements)

References 51 publications

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“…The CEC separations utilize predominantly reversed phase and ion-exchange modes, performed almost exclusively in buffered aqueous or aqueous/organic mixed electrolyte systems. Nonaqueous conditions have been used for chiral separations with polar organic mobile phases [43][44][45][46]. Size-based separation mechanisms have not been fully exploited in CEC, excluding capillary gel electrophoresis, which relies on sieving rather than size exclusion [47].…”

Section: Introductionmentioning

confidence: 99%

Size‐exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases

2003

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We report the successful size-based separations of large, neutral polysaccharides using capillary electrochromatography (CEC). As the polysaccharides possessed little chromophore for photometric detection, two separate approaches were taken. In the first approach, indirect detection was combined with size-exclusion chromatography using a sulfonated polystyrene/divinylbenzene stationary phase. The separations were performed using a 300 Å pore size stationary phase under aqueous conditions. Nonsize based interactions were minimal using this material, resulting in an effective calibration range of molecular masses 180 to 112 000 g?mol 21 for pullulans. In the second approach, the polysaccharides were derivatized with phenylisocyanate and were subsequently separated on columns made using a combination of high capacity ionexchanger and a neutral polystyrene/divinylbenzene material of various pore sizes. The sulfonated ion-exchange phase provided the electroosmotic flow, while the mixed pore size material provided the extended calibration range. The linear range for this primarily nonaqueous system using tetrahydrofuran was determined to be from molecular masses 738 to 404 000 g?mol 21 of the original, untagged pullulan. This approach overcame the limited solubility issue associated with analysis of some polysaccharides. Analysis of pullulan and amylose samples by CEC correlated well with results obtained by conventional high-performance liquid chromatography (HPLC). The sizeexclusion electrochromatographic separations provide an alternative mode for determining the relative molecular weights of polysaccharides with reduced sample and solvent consumption, as well as analysis times.

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Section: Introductionmentioning

confidence: 99%

Size‐exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases

2003

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“…CEC has rapidly gained interest among researchers in many different fields [1][2][3][4][5][6] during recent years since its theory and practice were introduced by Knox and Grant [7]. The three main modes of CEC (classified according to the type of capillary column used) are packed columns with retaining frits [8][9][10], monolithic capillary columns [11,12] and open-tubular (OT) capillary columns [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterisation of dual‐layer latex‐coated columns for open‐tubular capillary electrochromatographic preconcentration of cations combined in‐line with their separation by capillary electrophoresis

2006

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A dual-layer ion-exchange latex-coated column was prepared and characterised for on-capillary preconcentration of cations using an open-tubular ion-exchange CEC format. After preconcentration, the analyte cations were eluted with a transient isotachophoretic gradient and separated by CE. The latex double layer was established by first coating the negatively charged wall of the capillary with a layer of cationic quaternary ammonium anion-exchange Dionex AS5A latex particles (60 nm diameter), and then coating a layer of anionic sulphonated cation-exchange Dionex CS3 latex particles (300 nm diameter) onto the underlying AS5A layer. The adhesion of layers is based on electrostatic attractions. Several dual-layer capillaries were characterised for their EOF and ion-exchange capacity and this showed that coatings could be prepared reproducibly by a simple flushing procedure. The dual-layer columns exhibited a moderate, pH-independent EOF (ca. 26 x 10(-9 )m2V(-1)s(-1)) and an ion-exchange capacity of 57 microequiv./g (or 2.69 nequiv./column). Using an 8 cm length of coated capillary combined with a 72 cm length of untreated capillary, a method for on-line preconcentration and separation of monovalent organic bases, alkali metal ions and alkaline earth metal ions by CE was developed. Recoveries for the preconcentration step were 48% for 4-methylbenzylammonium, 43% for benzylammonium, 30-32% for alkali metal ions and 71-75% for alkaline earth cations. In all cases, recoveries were reproducible with RSDs being less than 6.2%. The influences of the ion-exchange selectivity coefficient of the analyte and the sample-loading rate on analyte recovery were also examined. The proposed method was utilised for the determination of alkaline earth cations and low microM detection limits were obtained.

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“…[16]. The same chiral selectors (TE and vancomycin) were also tested in CEC for the separation of mainly basic compounds [9,10,13,[17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of teicoplanin chiral stationary phases of 3.5 and 5 μm inside diameter silica microparticles by polar‐organic mode capillary electrochromatography

et al. 2003

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Different types of fused-silica capillaries of 75 microm inside diameter (ID) were packed, namely type A and B, and evaluated for the direct resolution of racemates of several basic compounds by enantioselective capillary electrochromatography (e-CEC). Type A was packed with a chiral stationary phase (CSP) containing teicoplanin (TE) mixed with silica microparticles (3:1 w/w) while type B contained only the TE-CSP. In both cases, particles of different sizes (3.5 and 5 microm ID) were employed. A polar-organic mobile phase containing methanol-acetonitrile (60-40% v/v and 0.05% w/v ammonium acetate was used. Several beta-blockers (alprenolol, oxprenolol, metoprolol, pindolol, salbutamol, propranolol, atenolol, acebutolol) were baseline-enantioresolved with both capillary types, in very short times.

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Evaluation of a Vancomycin Chiral Stationary Phase in Capillary Electrochromatography Using Polar Organic and Reversed-Phase Modes

Cited by 98 publications

References 51 publications

Size‐exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases

Size‐exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases

Preparation and characterisation of dual‐layer latex‐coated columns for open‐tubular capillary electrochromatographic preconcentration of cations combined in‐line with their separation by capillary electrophoresis

Evaluation of teicoplanin chiral stationary phases of 3.5 and 5 μm inside diameter silica microparticles by polar‐organic mode capillary electrochromatography

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