Chromatographic resolution

Okamoto, Yoshio; Kawashima, M.; Hatäda, Koichi

doi:10.1016/s0021-9673(01)83736-5

Cited by 666 publications

(242 citation statements)

References 23 publications

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“…Although a wide range of enantiomers have been resolved on these CSPs, their chiral recognition abilities on different cellulose derivatives are markedly complementary. In order to broaden the range of applications of a single CSP, several researchers [5,8,9] have tried to combine different substitutions at O-C(2,3) and O-C(6) of polysaccharide derivatives by regioselective procedures, and some interesting results have been observed with respect to enantioseparations. For example, some regioselectively substituted cellulose or amylose derivatives have exhibited a higher enantioselectivity than the homogeneously substituted cellulose or amylose triscarbamate [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characteristics of composite chiral stationary phases based on cellulose derivatives

Chen

Zou²,

et al. 2003

J of Separation Science

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Synthesis and characteristics of composite chiral stationary phases based on cellulose derivativesComposite chiral stationary phases (CSPs) were prepared on the basis of cellulose derivatives coated or bonded onto silica. "Molecular exterior" type CSPs were prepared by mixing together two different cellulose tris-derivatives before or after being coated or bonded onto silica, and the "molecular interior" type was obtained by synthesizing non-regioselectively heterosubstituted cellulose derivatives coated or bonded onto silica. For the sake of comparison, the individual phases were also prepared with corresponding cellulose derivatives by coating or bonding approaches, respectively. All of the prepared CSPs were characterized and their chiral recognition properties were evaluated by HPLC with several test racemates. The experimental results demonstrated that the "molecular exterior" CSPs generally exhibit chiral recognition capacities intermediate between those of the two individual phases. However, in the separation of some racemates higher enantioselectivity may be achieved on the "molecular interior" phases than on individual phases, thus broadening the application range of a single cellulose-based CSP.

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Section: Introductionmentioning

confidence: 99%

Synthesis and characteristics of composite chiral stationary phases based on cellulose derivatives

Chen

Zou²,

et al. 2003

J of Separation Science

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“…The resulting mixture was injected into the activated fused silica capillary up to the required length and allowed to react overnight at 35 o C. Then, the column was heated at 150 o C for 6 h. After completion of heating, the capillaries were cooled to room temperature and then characterized by SEM. CDMPC was prepared as per the reported method 43 and SCDMPC was prepared as per the reported method 42 and characterized by elemental analyses, IR and NMR spectroscopy. To perform the CDMPC and SCDMPC coatings on the surface of ZM bed, the ZM capillaries were initially washed with ethanol and then with THF.…”

Section: Dmentioning

confidence: 99%

Chiral Separation on Sulfonated Cellulose Tris(3,5-dimethylphenylcarbamate)-coated Zirconia Monolith by Capillary Electrochromatography

Lee¹,

Jang²,

Park³

2012

Bulletin of the Korean Chemical Society

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Sulfonated cellulose tris(3,5-dimethylphenylcarbamate) (SCDMPC)-coated zirconia monolith (ZM) was used as the chiral stationary phase in capillary electrochromatography for separation of enantiomers of ten chiral compounds in acetonitrile (ACN)-phosphate buffer mixtures as the eluent. Influences of the ACN content, buffer concentration and pH on chiral separation have been investigated. Separation data on SCDMPC-ZM have been compared with those on CDMPC-ZM. Resolution factors were better on SCDMPC-ZM than CDMPC-ZM while retention factors were in general shorter on the former than the latter. Best chiral resolutions on SCDMPC-ZM were obtained with the eluent of 50% ACN containing 50 mM phosphate at pH around 4.Key Words : Chiral separation, Zirconia monolith, Sulfonated cellulose 3,5-dimethylphenylcarbamate, Capillary electrochromatography IntroductionCapillary electrochromatography (CEC) is a hybrid technique of HPLC and CE, and has been increasingly utilized in studies on the development and evaluation of separation methods including chiral separations.1-3 It provides high efficiency because of the flat profile of electroosmotic flow (EOF) to pump the mobile phase and ability to separate charged as well as uncharged compounds through electrophoresis and chromatographic separation.3 Several reviews have been reported on enantioseparations using CEC as a separation technique.1-4 Three types of columns including, open-tubular, particulate-packed and monolithic capillaries are used for CEC.5 Monolithic columns are becoming attractive alternative to particle-packed columns in HPLC and electrochromatography.6-8 Monolithic columns are devoid of problems and difficulties associated with packed capillary columns, including burdensome packing of stationary phase particles in a capillary and frits that cause formation of air bubbles during the analysis which results in reduction of separation efficiency, and tend to break easily.9-12 The monolithic columns allow fast mass transfer at lower pressure drops, enabling much faster separations. The continuous monolithic bed in the capillary column also allows high linear velocities that enable high throughput screening and fast separations of enantiomers. 6-8,13Among various classes of chiral selectors 14,15 polysaccharides have been widely used as the chiral stationary phase (CSP). A great number of polysaccharide derivatives including cellulose, amylose, chitin, chitosan, galactosamine, curdlan, dextran, xylan, and inulin have been in use for chiral separations. 16 The derivatives of cellulose and amylose usually exhibit higher chiral recognition ability than the other type polysaccharides. A number of HPLC separations for a large number of chiral compounds in different classes on polysaccharide-immobilized silica 17-20 and polymer columns.21 The polysaccharide-based columns can be used in normal phase, polar organic and reversed-phase mode. 22While silica-based stationary phases have received wide acceptance due to their well-studied surface chemistry, drawbacks of silica-ba...

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“…Cellulose tris(3,5-dimethylphenylcarbamate) was synthesized as previously reported 5 and characterized by elemental analyses, IR and NMR spectroscopy. Typically, 1.0 g of dehydroxylated bare zirconia particles were suspended in 10 mL of THF and sonicated under vacuum for 15 min to eliminate the air from the pores.…”

Section: Preparation Of Cdmpc-coated Zirconiamentioning

confidence: 99%

“…1 One of the major problems in using many CSPs is their narrow range of analyte applicability; they can only discriminate a limited number of specific types of chemical entities, and it is frequently necessary to derivatize the compounds of interest to achieve separation. 2 On the other hand, the polysaccharide derivative-based CSPs developed by Okamoto and coworkers [3][4][5][6][7] have proven to be highly versatile and rugged. Okamoto reported that the resolution of 483 racemic mixtures on cellulose and that 80% of them were successfully resolved on either the cellulose or amylose tris(3,5-dimethylphenylcarbamate) (CDMPC or ADMPC).…”

mentioning

confidence: 99%

Cellulose Dimethylphenylcarbamate-bonded Carbon-clad Zirconia for Chiral Separation in High Performance Liquid Chromatography

et al. 2006

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HPLC based on chiral stationary phases (CSPs) has become one of the most attractive approaches to chiral separations, due to their simplicity for determining optical purity and easy extension to the semipreparative and preparative scales. 1 One of the major problems in using many CSPs is their narrow range of analyte applicability; they can only discriminate a limited number of specific types of chemical entities, and it is frequently necessary to derivatize the compounds of interest to achieve separation. 2 On the other hand, the polysaccharide derivative-based CSPs developed by Okamoto and coworkers [3][4][5][6][7] have proven to be highly versatile and rugged. Okamoto reported that the resolution of 483 racemic mixtures on cellulose and that 80% of them were successfully resolved on either the cellulose or amylose tris(3,5-dimethylphenylcarbamate) (CDMPC or ADMPC). 8 Silica is the most popular choice for support of HPLC stationary phase ligands due to the mechanical strength, wide range of particle and pore dimensions, pore structure and wellestablished silane chemistry. However, silica and bonded phase ligands have stability problems. Silica dissolves in mobile phase buffered at or above pH 8 with loss of bonded phase ligand and column packing. 9 Loss of organosilanes from the silica surface via hydrolysis proceeds rapidly at low pH (< 3) and at high temperature (≥ 40˚C). These deficiencies of the column packing create problems of poor injection reproducibility, poor peak shape, and high backpressure, thus making method development tasks difficult. Siloxane-bonded silica phases with improved hydrolytic stability at extreme pH for use in reversedphase liquid chromatography were introduced. 10-13 However, careful choices of operating conditions, such as the use of acetonitrile instead of methanol, the use of boric acid or organic buffers in low concentration and low temperature, are still required to achieve acceptable column lifetimes. [14][15][16][17] Zirconia particles are very robust material; they show no detectable signs of dissolution over the pH range from 1 to 14 and have been used for prolonged periods at temperatures up to 200˚C in chromatographic separations. Thus, zirconia has received considerable attention as a stationary phase support for HPLC over the last decade. 18,19 One of us has been working to develop efficient and chemically stable CSPs on zirconia substrates. [20][21][22][23] Bare zirconia cannot be covalently modified like silica due to the instability of Zr-C and Zr-O-Si bonds in water. 24 Zirconia-based CSPs reported have thus been prepared by coating chiral selectors on zirconia surface by utilizing Lewis acid-base chemistry. Recently we reported chiral separation of N- (2,4-dinitrophenyl) Porous zirconia particles are very robust material and have received considerable attention as a stationary phase support for HPLC. We prepared cellulose dimethylphenylcarbamate-bonded carbon-clad zirconia (CDMPCCZ) as a chiral stationary phase (CSP) for separation of enantiomers of a set of...

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Chromatographic resolution

Cited by 666 publications

References 23 publications

Synthesis and characteristics of composite chiral stationary phases based on cellulose derivatives

Synthesis and characteristics of composite chiral stationary phases based on cellulose derivatives

Chiral Separation on Sulfonated Cellulose Tris(3,5-dimethylphenylcarbamate)-coated Zirconia Monolith by Capillary Electrochromatography

Cellulose Dimethylphenylcarbamate-bonded Carbon-clad Zirconia for Chiral Separation in High Performance Liquid Chromatography

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