Heterogeneity of adsorption mechanisms in chiral normal-phase liquid chromatography

Cavazzini, Alberto; Nadalini, Giorgio; Costa, Valentina; Dondi, Francesco

doi:10.1016/j.chroma.2006.12.090

Cited by 12 publications

(7 citation statements)

References 36 publications

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“…Also, as shown by Felinger, the proper investigation of the initial region of the adsorption isotherm requires the acquisition of a large number of data points in the linear range of the isotherm, particularly if the density of high-energetic sites is low. The PM is preferred for the investigation and the interpretation of the adsorption of organic modifiers on reversed-phase adsorbent. ,, In NPLC conditions, however, this method presents a drawback due to the difficulty of detecting linear perturbation peaks of strong modifiers in columns equilibrated with a weak solvent …”

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confidence: 99%

Adsorption Mechanisms in Normal-Phase Chromatography. Mobile-Phase Modifier Adsorption from Dilute Solutions and Displacement Effect

et al. 2007

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The adsorption equilibria of methanol from diluted solutions of the alcohol in dichloromethane (the weak solvent of the binary mixture) have been investigated in normal-phase conditions on an hybrid polymeric chiral stationary phase. This was done by analyzing the shapes of nonlinear perturbations of methanol, measured with a refractive index detector from a column in equilibrium with pure dichloromethane. Experiments have been set up to demonstrate the displacement effect, predictable from the adsorption data, by a nonlinear pulse of methanol on a racemic mixture of temazepam injected at trace level. A most used method in fundamental studies of band behavior in chromatography has been used for modeling the system. An extraordinary increase of the apparent column efficiency has been observed due to the displacement phenomenon, with the peak of the second eluted enantiomer noticeably higher and narrower than that of the first eluted component.

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confidence: 99%

Adsorption Mechanisms in Normal-Phase Chromatography. Mobile-Phase Modifier Adsorption from Dilute Solutions and Displacement Effect

et al. 2007

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“…This technique is just beginning to gain popularity in chiral chromatography. It has been used to study the adsorption of binary eluents on chiral stationary phases (CSPs) Whelk-O1 [9], DACH-ACR [10], and Chiralcel OD-I [11]. The adsorption of aqueous organic solvents was used to study the surface properties of CSPs with grafted macrocyclic antibiotics in [12,13], and the authors of [14] investigated the effect the composition of an adsorbed layer of the mobile phase has on the mechanism of amino acid retention on antibiotic columns.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Binary Solvents on Chiral Stationary Phases with Grafted Macrocyclic Antibiotics

Klimova

2021

Russ. J. Phys. Chem.

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A study is performed of the adsorption of water–methanol and water–acetonitrile mixtures on chiral stationary phases (CSPs) Chirobiotic R, Chirobiotic T, and Nautilus-E with grafted macrocyclic antibiotics ristocetin A, teicoplanin, and eremomycin, respectively. The patterns of adsorption on the indicated CSPs are qualitatively the same, and differ only by quantitative indicators. Adsorption isotherms of excess water from binary solvents have adsorption azeotrope points and show the preferred absorption of water in the range of pure organic component to an azeotrope point in the range of 60–75 mol % for H2О–МеОН and 80–90 mol % for H2O–MeCN systems. It is shown that the thickness of the adsorption phase in the first case is less than one nominal molecular layer (0.10–0.13 nm). For H2O–MeCN, it is 3–4 molecular layers (0.88–1.05 nm). Activity coefficients are calculated for the components of solutions in surface layers. The coefficients indicate the systems deviate considerably from the properties of an ideal adsorption solution. Reasons for this behavior are discussed.

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“…Many factors can be responsible for the extent of interactions of stereoisomeric molecules with immobilized polysaccharide‐based chiral stationary phase such as dipole–dipole interactions, electrostatic forces, hydrogen bonding, hydrophobic bonding, ion–dipole interactions, steric interferences (size, orientation, and spacing of groups), and Van der Waals forces. The nature and effects of some of these factors can influence the chromatography of enantiomers …”

Section: Introductionmentioning

confidence: 99%

“…The nature and effects of some of these factors can influence the chromatography of enantiomers. 5,6 Molecular modeling studies have succeeded in interpreting many ligand-receptor mechanisms depending on the basic interactions that occur between the ligand and its site of action. Moreover, in addition, some other factors such as the binding affinity of the ligand or receptor strain have been demonstrated.…”

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confidence: 99%

HPLC‐Fluorescence Method for the Enantioselective Analysis of Propranolol in Rat Serum Using Immobilized Polysaccharide‐Based Chiral Stationary Phase

et al. 2014

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A stereoselective high-performance liquid chromatographic (HPLC) method was developed and validated to determine S-(-)- and R-(+)-propranolol in rat serum. Enantiomeric resolution was achieved on cellulose tris(3,5-dimethylphenylcarbamate) immobilized onto spherical porous silica chiral stationary phase (CSP) known as Chiralpak IB. A simple analytical method was validated using a mobile phase consisted of n-hexane-ethanol-triethylamine (95:5:0.4%, v/v/v) at a flow rate of 0.6 mL min(-1) and fluorescence detection set at excitation/emission wavelengths 290/375 nm. The calibration curves were linear over the range of 10-400 ng mL(-1) (R = 0.999) for each enantiomer with a detection limit of 3 ng mL(-1). The proposed method was validated in compliance with ICH guidelines in terms of linearity, accuracy, precision, limits of detection and quantitation, and other aspects of analytical validation. Actual quantification could be made for propranolol isomers in serum obtained from rats that had been intraperitoneally (i.p.) administered a single dose of the drug. The proposed method established in this study is simple and sensitive enough to be adopted in the fields of clinical and forensic toxicology. Molecular modeling studies including energy minimization and docking studies were first performed to illustrate the mechanism by which the active enantiomer binds to the β-adrenergic receptor and second to find a suitable interpretation of how both enantiomers are interacting with cellulose tris(3,5-dimethylphenylcarbamate) CSP during the process of resolution. The latter interaction was demonstrated by calculating the binding affinities and interaction distances between propranolol enantiomers and chiral selector.

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Heterogeneity of adsorption mechanisms in chiral normal-phase liquid chromatography

Cited by 12 publications

References 36 publications

Adsorption Mechanisms in Normal-Phase Chromatography. Mobile-Phase Modifier Adsorption from Dilute Solutions and Displacement Effect

Adsorption Mechanisms in Normal-Phase Chromatography. Mobile-Phase Modifier Adsorption from Dilute Solutions and Displacement Effect

Adsorption of Binary Solvents on Chiral Stationary Phases with Grafted Macrocyclic Antibiotics

HPLC‐Fluorescence Method for the Enantioselective Analysis of Propranolol in Rat Serum Using Immobilized Polysaccharide‐Based Chiral Stationary Phase

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