Chiral Separations By Liquid Chromatography And Related Technologies

Aboul‐Enein, Hassan Y.; Ali, Imran

doi:10.1201/9780203911112

Cited by 155 publications

(150 citation statements)

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“…The buffer for acidic to neutral pH range (pH 6.0-7.0) was prepared by dissolving either 15, 25 or 40 mM ammonium acetate in water and titrated with CH 3 COOH to the desired pH. For pseudoephedrine assay in human urine by MEKC-MS, 15 mM TEA and 15 mM NH 4 OAc were dissolve in water and HCOOH was used to obtain pH 2.0 buffer. For enantioseparation of β-blockers at pH 2.0, 25 mM NaH 2 PO 4 and 25 mM CH 3 COONa were dissolved in water and pH was adjusted using H 3 PO 4 .…”

Section: Preparation Of Mekc Buffers Analyte Solutions and Human Urimentioning

confidence: 99%

“…For enantioseparation of β-blockers at pH 2.0, 25 mM NaH 2 PO 4 and 25 mM CH 3 COONa were dissolved in water and pH was adjusted using H 3 PO 4 . For enantioseparation of β-blockers at basic pH 8.0, 25 mM NH 4 OAc and 25 mM TEA were dissolved in water and pH was adjusted using CH 3 COOH. For enantioseparation of 2-PPA, benzoin derivatives, PTH-amino acids and benzodiazepenes at acidic pH (2.0 or 3.0) and at basic pH (8.0), the same buffers were used as for enantioseparation of β-blockers (see above) at the respective acidic and basic pH.…”

Section: Preparation Of Mekc Buffers Analyte Solutions and Human Urimentioning

confidence: 99%

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Polymeric Sulfated Amino Acid Surfactants: A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

et al. 2006

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In this work, three amino acids derived (L-leucinol, L-isoleucinol and L-valinol) sulfated chiral surfactants are synthesized and polymerized. These chiral sulfated surfactants are thoroughly characterized to determine critical micelle concentration, aggregation number, polarity, optical rotation and partial specific volume. For the first time the morphological behavior of polymeric sulfated surfactants is revealed using cryogenic high-resolution electron microscopy (cryo-HRSEM). The polysodium N-undecenoyl-L-leucine sulfate (poly-L-SUCLS) shows distinct tubular structure, while polysodium N-undecenoyl-L-valine sulfate (poly-L-SUCVS) also shows tubular morphology but without any distinct order of the tubes. On the other hand, polysodium N-undecenoyl-Lisoleucine sulfate (poly-L-SUCILS) displays random distribution of coiled/curved filaments with heavy association of tightly and loosely bound water. All three polymeric sulfated surfactants are compared for enantio-separation of broad range of structurally diverse racemic compounds at very acidic, neutral and basic pH conditions in micellar electrokinetic chromatography (MEKC). A small combinatorial library of 10 structurally related phenylethylamines (PEAs) is investigated for chiral separation under acidic and moderately acidic to neutral pH conditions using an experimental design. In contrast to neutral pH conditions, at acidic pH, significantly enhanced chiral resolution is obtained for class I and class II PEAs due to the compact structure of polymeric sulfated surfactants. It is observed that the presence of hydroxy group on the benzene ring of PEAs resulted in deterioration of enantioseparation. A sensitive MEKC-mass spectrometry (MS) method is developed for one of the PEA (e.g., (±)-pseudoephedrine) in human urine. Very low limit of detection (LOD) is obtained at pH 2.0 (LOD 325 ng/mL), which is ca 16 times better compared to pH 8.0 (LOD 5.2 µg/mL). Other broad range of chiral analytes (β-blockers, phenoxypropionic acid, benzoin derivatives, PTHamino acids, and benzodiazepinones) studied also provided improved chiral separation at low pH compared to high pH conditions. Among the three polymeric sulfated surfactants, poly-L-SUCILS with two chiral centers on the polymer head group provided overall higher enantioresolution for the investigated acidic, basic and neutral compounds. This work clearly demonstrates for the first time the superiority of chiral separation and sensitive MS detection at low pH over conventional high pH chiral separation and detection employing anionic chiral polymeric surfactants in MEKC and MEKC-MS. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptOver the last 20 years, the number of materials and products developed as pure enantiomers (eutomer) has continued to increase. With evidence of problems related to stereoselectivity in drug action, enantioselective analysis by separation are of particular importance for production, therapeutic monitoring or pharmacokinetic studies, and/or to validate the opt...

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Section: Preparation Of Mekc Buffers Analyte Solutions and Human Urimentioning

confidence: 99%

Section: Preparation Of Mekc Buffers Analyte Solutions and Human Urimentioning

confidence: 99%

Polymeric Sulfated Amino Acid Surfactants: A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

et al. 2006

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“…High performance liquid chromatography (HPLC) on chiral stationary phases (CSPs) is among the most general and powerful techniques for separation of optical isomers [8][9][10][11][12][13]. The efficiency of the separation is strongly dependant on the structure of the stationary phase (SP) used.…”

Section: Introductionmentioning

confidence: 99%

Enantioresolution of a Series of Chiral Benzyl Alcohols by HPLC on a Dinitrobenzoylphenylglycine Stationary Phase after Achiral Pre-Column Derivatization*

Simeonov¹,

Simeonov²,

Todorov³

et al. 2010

AJAC

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High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral derivatization was developed. Cheap and easy available aromatic acid chlorides were used as derivatization agents. Good to excellent separations of the enantiomers were achieved in all cases in relatively short analytical runs. It was shown that the enantiorecognition depends on the substituents both in the starting alcohol and in the acid chloride. The method presents an efficient alternative to the direct analyses on polysaccharide and cyclodextrine-derived stationary phases.

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“…Among these, polysaccharide based CSPs are important due to their wide ranges of applications [5]. It is interesting to note that all available polysaccharide chiral stationary phases are coated on silica support, which restricts the uses of some prohibited solvents such as tetrahydrofuran (THF), chlorofom, dichloromethane, ethylacetate, pyridine, acetone, and certain ethers as eluents [5,6]. Due to these facts, coated CSPs are not capable to resolve certain drugs and pharmaceuticals, especially in the reaction mixtures having prohibited solvents.…”

Section: Introductionmentioning

confidence: 99%

Pharmacokinetic Development of a Sensitive and Stereoselective HPLC Method for the Analysis of Pindolol in Plasma and Pharmaceutical Products Using a Chiralpak IB Column and Fluorescence Detection

Hefnawy¹,

Kassem²,

Abdine³

et al. 2009

Sci. Pharm.

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A sensitive and stereoselective HPLC method has been developed for the simultaneous determination of pindolol enantiomers in plasma and pharmaceutical products. Enantiomeric resolution was achieved on a cellulose tris(3,5-dimethylphenylcarbamate) immobilized onto a 5 µm spherical porous silica chiral stationary phase (CSP) known as Chiralpak IB with fluorescence detection set at 266 nm for excitation and 308 nm for emission. The mobile phase consists of n-hexane-isopropanol-triethylamine, (50:50:0.5), (v/v/v) has been used at a flow rate of 1.0 ml/min. The method was highly specific where other coformulated drugs such as clopamide and isosorbide did not interfere. The stability of pindolol enantiomers under different degrees of temperature was studied. The method validated for its linearity, accuracy, precision and robustness. There was no significant difference (p>0.05) between inter-and intra-day studies for each enantiomers which confirmed the reproducibility of the assay method. Preliminary data suggest that S-(−)-pindolol induces less bradycardia but more sedation and central nervous system depression than racemic pindolol.

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Chiral Separations By Liquid Chromatography And Related Technologies

Cited by 155 publications

References 0 publications

Polymeric Sulfated Amino Acid Surfactants: A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

Polymeric Sulfated Amino Acid Surfactants: A Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

Enantioresolution of a Series of Chiral Benzyl Alcohols by HPLC on a Dinitrobenzoylphenylglycine Stationary Phase after Achiral Pre-Column Derivatization*

Pharmacokinetic Development of a Sensitive and Stereoselective HPLC Method for the Analysis of Pindolol in Plasma and Pharmaceutical Products Using a Chiralpak IB Column and Fluorescence Detection

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