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Peluso P, Chankvetadze B. Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers. Chem Rev 2022; 122:13235-13400. [PMID: 35917234 DOI: 10.1021/acs.chemrev.1c00846] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as "multistep" processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.
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Affiliation(s)
- Paola Peluso
- Istituto di Chimica Biomolecolare ICB, CNR, Sede secondaria di Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, I-07100 Sassari, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Avenue 3, 0179 Tbilisi, Georgia
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2
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Felletti S, De Luca C, Lievore G, Chenet T, Chankvetadze B, Farkas T, Cavazzini A, Catani M. Shedding light on mechanisms leading to convex-upward van Deemter curves on a cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral stationary phase. J Chromatogr A 2020; 1630:461532. [PMID: 32950816 DOI: 10.1016/j.chroma.2020.461532] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 11/16/2022]
Abstract
An unusual convex-upward van Deemter curve was observed for the more retained enantiomer of a chiral sulfoxide (2-(benzylsulfinyl)benzamide) on a cellulose tris(4-chloro-3-methylphenylcarbamate)-based chiral stationary phase (CSP), prepared on silica particles of 1000 Å pore size. In contrast, the firstly eluted enantiomer of the same molecule exhibited the traditional convex-downward van Deemter curve. A detailed kinetic and thermodynamic investigation has revealed that this unusual phenomenon, which however has already been observed in chiral chromatography, originates when the adsorption of the compound is very strong and the solid-phase diffusion negligible. Experimentally, the intraparticle diffusion of the more retained enantiomer of the sulfoxide was found to be one order of magnitude smaller than that of the first eluted one. Overall, this translates into very little longitudinal diffusion (b-term of van Deemter curve) accompanied by high solid-liquid mass transfer resistance (c-term). Finally the comparison with another, differently-substituted chiral sulfoxide (whose enantiomers both exhibit traditional van Deemter curve behavior) has allowed to correlate these findings to the specific characteristics of the molecule.
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Affiliation(s)
- Simona Felletti
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Chiara De Luca
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Giulio Lievore
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Tatiana Chenet
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy
| | - Bezhan Chankvetadze
- Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179 Tbilisi, Georgia
| | - Tivadar Farkas
- Phenomenex Inc., 411 Madrid Ave., Torrance, CA 90501, United States
| | - Alberto Cavazzini
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy.
| | - Martina Catani
- Department of Chemistry and Pharmaceutical Sciences, University of Ferrara, via L. Borsari 46, 44121 Ferrara, Italy.
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Felletti S, De Luca C, Ismail OH, Pasti L, Costa V, Gasparrini F, Cavazzini A, Catani M. On the effect of chiral selector loading and mobile phase composition on adsorption properties of latest generation fully- and superficially-porous Whelk-O1 particles for high-efficient ultrafast enantioseparations. J Chromatogr A 2018; 1579:41-48. [DOI: 10.1016/j.chroma.2018.10.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 10/09/2018] [Accepted: 10/14/2018] [Indexed: 11/28/2022]
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5
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The modeling of overloaded elution band profiles in supercritical fluid chromatography. J Chromatogr A 2014; 1333:116-23. [DOI: 10.1016/j.chroma.2014.01.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/11/2014] [Accepted: 01/13/2014] [Indexed: 11/22/2022]
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6
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Adsorption models in chiral chromatography. J Chromatogr A 2012; 1269:3-25. [DOI: 10.1016/j.chroma.2012.08.096] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 08/26/2012] [Accepted: 08/28/2012] [Indexed: 12/20/2022]
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7
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Chankvetadze B. Recent developments on polysaccharide-based chiral stationary phases for liquid-phase separation of enantiomers. J Chromatogr A 2012; 1269:26-51. [DOI: 10.1016/j.chroma.2012.10.033] [Citation(s) in RCA: 329] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/11/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
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8
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Asnin LD, Kaczmarski K, Reshetova EN. Adsorption of naproxen enantiomers from solutions on chemically modified cellulose. The effect of a polar component of a liquid phase. Russ Chem Bull 2010. [DOI: 10.1007/s11172-009-0239-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Ståhlberg J. The thermodynamic limit of linear gradient chromatography. J Chromatogr A 2010; 1217:3172-9. [DOI: 10.1016/j.chroma.2010.02.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/15/2010] [Accepted: 02/17/2010] [Indexed: 11/29/2022]
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10
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Samuelsson J, Arnell R, Fornstedt T. Potential of adsorption isotherm measurements for closer elucidating of binding in chiral liquid chromatographic phase systems. J Sep Sci 2009; 32:1491-506. [DOI: 10.1002/jssc.200900165] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Szabelski P, Kaczmarski K. Phenomenological modeling of separation of enantiomers by nonlinear chromatography. ACTA CHROMATOGR 2008. [DOI: 10.1556/achrom.20.2008.4.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Asnin LD. Adsorption of naproxen enantiomers on chemically modified cellulose. Russ Chem Bull 2008. [DOI: 10.1007/s11172-007-0379-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cavazzini A, Nadalini G, Malanchin V, Costa V, Dondi F, Gasparrini F. Adsorption Mechanisms in Normal-Phase Chromatography. Mobile-Phase Modifier Adsorption from Dilute Solutions and Displacement Effect. Anal Chem 2007; 79:3802-9. [PMID: 17441684 DOI: 10.1021/ac062240o] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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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Affiliation(s)
- Alberto Cavazzini
- Department of Chemistry, University of Ferrara, via L. Borsari 46, 44100 Ferrara, Italy.
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Lindholm J, Forssén P, Fornstedt T. Validation of the accuracy of the perturbation peak method for determination of multicomponent adsorption isotherm parameters in LC. Anal Chem 2006; 76:5472-8. [PMID: 15362909 DOI: 10.1021/ac049632k] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The isotherm parameters were for the first time determined for a quaternary mixture. This was done by the perturbation peak (PP) method using racemic mixtures of methyl and ethyl mandelate enantiomers. One complication with the PP method is that the traditional blank injection technique makes all perturbation peaks, except one, vanish at moderately nonlinear concentration plateaus. Therefore, we devised a new injection technique that made all four peaks on a quaternary component concentration plateau detectable, thereby making the determination of multicomponent competitive isotherm parameters possible. The measured quaternary perturbation data fitted well to the bi-Langmuir isotherm model and excellent agreement was found between experimental and simulated single-component and multicomponent profiles, thus validating the method and the determined isotherm parameters. The method (i) is valuable for computer-assisted optimization of preparative chiral chromatography and (ii) opens the possibility of quantifying competitive drug-target interactions for chiral drugs directly on racemic mixtures, which today is impossible with any nonlabeled technique including surface plasmon resonance technology.
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Affiliation(s)
- Johan Lindholm
- Department for Surface Biotechnology, Uppsala University, BMC, Box 577, S-751 23, Uppsala, Sweden
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Asnin L, Kaczmarski K, Felinger A, Gritti F, Guiochon G. Adsorption of the enantiomers of 3-chloro-1-phenyl-propanol on silica-bonded chiral quinidine carbamate. J Chromatogr A 2006; 1101:158-70. [PMID: 16236290 DOI: 10.1016/j.chroma.2005.09.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 09/23/2005] [Accepted: 09/27/2005] [Indexed: 11/17/2022]
Abstract
The interactions of 3-chloro-1-phenyl-propanol with a quinidine carbamate-bonded chiral stationary phase under NPLC conditions were studied by measuring the adsorption isotherm data of its enantiomers by frontal analysis, modeling these data with a suitable isotherm model, and comparing the experimental overloaded elution band profiles with those calculated with this isotherm and the equilibrium dispersive model of liquid chromatography. The affinity energy distribution was calculated from the adsorption isotherm data. The results show that the surface of the adsorbent is heterogeneous and exhibits a bimodal adsorption energy distribution. This fact is interpreted in terms of the presence of two different types of adsorption sites on the stationary phase, nonselective and enantioselective sites. Albeit the bi-Langmuir isotherm model successfully accounts for the single-component data corresponding to both enantiomers, the competitive bi-Langmuir isotherm model does not allow an accurate prediction of the overloaded band profiles of the racemic mixture. Thermodynamic data are drawn for explanation. Some aspects of the retention mechanism are discussed in the light of the data obtained.
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Affiliation(s)
- Leonid Asnin
- Department of Chemistry, University of Tennessee, Knoxville TN 37996-1600, USA
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Lindholm J, Fornstedt T. Investigation of the adsorption behaviour of a chiral model compound on a tartardiamide-based network-polymeric chiral stationary phase. J Chromatogr A 2005; 1095:50-9. [PMID: 16275282 DOI: 10.1016/j.chroma.2005.07.122] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 07/25/2005] [Accepted: 07/28/2005] [Indexed: 10/25/2022]
Abstract
The adsorption behaviour of the enantiomers of 2-phenylbutyric acid on the chiral stationary phase (CSP) Kromasil CHI-TBB was studied using hexane/MTBE (90/10) as eluent. Adsorption isotherms were acquired at 40 different enantiomer concentrations in the interval between 7.6 microM and 305 mM, an approximately 40,000-fold dynamic range. The adsorption data fitted well to the bi-Langmuir model, indicating a heterogeneous surface with two different types of adsorption sites having different equilibrium constants and capacities; namely one chiral site and one non-chiral site. A comparison with earlier adsorption studies on modern CSPs revealed that the capacity value of the "true" chiral site of Kromasil CHI-TBB is the largest reported so far. The elution profiles simulated with these parameters show excellent agreement with the corresponding experimental profiles. Guidelines for comparisons of loading capacities of CSPs are presented.
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Affiliation(s)
- Johan Lindholm
- Department of Surface Biotechnology, Uppsala University, BMC, Sweden
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18
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Marchetti N, Dondi F, Felinger A, Guerrini R, Salvadori S, Cavazzini A. Modeling of overloaded gradient elution of nociceptin/orphanin FQ in reversed-phase liquid chromatography. J Chromatogr A 2005; 1079:162-72. [PMID: 16038302 DOI: 10.1016/j.chroma.2005.02.078] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Reversed-phase (RP) gradient elution chromatography of nociceptin/orphanin FQ (N/OFQ), a neuropeptide with many biological effects, has been modeled under linear and non-linear conditions. In order to do this, the chromatographic behavior has been studied under both linear and nonliner conditions under isocratic mode at different mobile phase compositions--ranging from 16 to 19% (v/v) acetonitrile (ACN) in aqueous trifluoracetic acid (TFA) 0.1% (v/v)-on a C-8 column. Although the range of mobile phase compositions investigated was quite narrow, the retention factor of this relatively small polypeptide (N/OFQ is a heptadecapeptide) has been found to change by more than 400%. In these conditions, gradient operation resulted thus to be the optimum approach for non-linear elution. As the available amount of N/OFQ was extremely reduced (only a few milligrams), the adsorption isotherms of the peptide, at the different mobile phase compositions examined, have been measured through the so-called inverse method (IM) on a 5 cm long column. The adsorption data at different mobile phase compositions have been fitted to several models of adsorption. The dependence of the isotherm parameters on the mobile phase composition was modeled by using the linear solvent strength (LSS) model and a generalized Langmuir isotherm that includes the mobile phase composition dependence. The overloaded gradient separation of N/OFQ has been modeled by numerically solving the equilibrium-dispersive (ED) model of chromatography under a selected gradient elution mode, on the basis of the previously determined generalized Langmuir isotherm. The agreement between theoretical calculations and experimental overloaded band profiles appeared reasonably accurate.
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Affiliation(s)
- Nicola Marchetti
- Department of Chemistry, University of Ferrara via L. Borsari 46, 44100 Ferrara, Italy
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19
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Cavazzini A, Dondi F, Marmai S, Minghini E, Massi A, Villani C, Rompietti R, Gasparrini F. Adsorption Equilibria of Benzodiazepines on a Hybrid Polymeric Chiral Stationary Phase. Anal Chem 2005; 77:3113-22. [PMID: 15889899 DOI: 10.1021/ac048101t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chromatographic behavior of a series of racemic benzodiazepines was evaluated under linear and nonlinear conditions on a new hybrid polymeric (DACH-ACR) chiral stationary phase (CSP). Differently substituted benzodiazepines were employed as probes to make hypotheses concerning possible molecular interaction mechanisms originating between target compounds and active sites on the CSP. Hydrogen bonds were found to be pivotal for chromatographic retention and chiral selectivity. The competitive effect from a mobile-phase (MP) modifier able to interact with the CSP through H-bonds was investigated. The performance of the polymeric DACH-ACR CSP for preparative purposes was also evaluated. The competitive adsorption isotherms of two benzodiazepines, lorazepam and temazepam, were measured at different MP compositions through the so-called inverse method. The adsorption data were fitted with a competitive bi-Langmuir adsorption isotherm. Enantiomeric separations under nonlinear conditions were modeled by using the equilibrium dispersive (ED) model of chromatography. Theoretical overloaded band profiles (obtained by solving the system of partial differential equations described by the ED model) matched, in a significantly accurate way, the profiles experimentally measured.
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Affiliation(s)
- Alberto Cavazzini
- Department of Chemistry, University of Ferrara, via L. Borsari 46, 44100 Ferrara, Italy.
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Hao W, Wang J. Evaluation of nonlinear chromatographic performance by frontal analysis using a simple multi-plate mathematical model. J Chromatogr A 2005; 1063:47-56. [PMID: 15700456 DOI: 10.1016/j.chroma.2004.11.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A multi-plate (MP) mathematical model was proposed by frontal analysis to evaluate nonlinear chromatographic performance. One of its advantages is that the parameters may be easily calculated from experimental data. Moreover, there is a good correlation between it and the equilibrium-dispersive (E-D) or Thomas models. This shows that it can well accommodate both types of band broadening that is comprised of either diffusion-dominated processes or kinetic sorption processes. The MP model can well describe experimental breakthrough curves that were obtained from membrane affinity chromatography and column reversed-phase liquid chromatography. Furthermore, the coefficients of mass transfer may be calculated according to the relationship between the MP model and the E-D or Thomas models.
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Affiliation(s)
- Weiqiang Hao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116012, PR China
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21
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Götmar G, Asnin L, Guiochon G. Adsorption of the enantiomers of 2,2,2-trifluoro-1-(9-anthryl)-ethanol on silica-bonded chiral quinidine-carbamate. J Chromatogr A 2004; 1059:43-52. [PMID: 15628123 DOI: 10.1016/j.chroma.2004.10.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The adsorption isotherms of the enantiomers of 2,2,2-trifluoro-1-(9-anthryl)-ethanol from a toluene-acetonitrile solution onto a Chiris Chiral AX:QD1 column were measured using the pulse method. The isotherm data were modeled with a bi-Langmuir isotherm model, indicating the presence of two different types of adsorption sites on this stationary phase, nonselective and enantioselective sites. The latter are homogeneous but interact with both enantiomers, albeit with different energies. The thermodynamic characteristics of these two types of sites were characterized by their adsorption constants and saturation capacities and by the influence of the temperature on these different parameters.
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Affiliation(s)
- Gustaf Götmar
- Department of Chemistry, The University of Tennessee, Knoxville, TN 37996-1600, USA.
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Choi SO, Lee SH, Choo HYP. Prediction on the chiral behaviors of drugs with amine moiety on the chiral cellobiohydrolase stationary phase using a partial least square method. Arch Pharm Res 2004; 27:1009-15. [PMID: 15554255 DOI: 10.1007/bf02975422] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Quantitative Structure-Resolution Relationship (QSRR) using the Comparative Molecular Field Analysis (CoMFA) software was applied to predict the chromatographic behaviors of chiral drugs with an amine moiety on the chiral cellobiohydrolase (CBH) columns. As a result of the Quantitative CoMFA-Resolution Relationship study, using the partial least square method, prediction of the behavior of drugs with amine moiety upon chiral separation became possible from their three dimensional molecular structures. When a mixed mobile phase of 10 mM aqueous phosphate buffer (pH 7.0) - isopropanol (95:5) was employed, the best Quantitative CoMFA-Resolution Relationship, derived from the study, provided a cross-validated q2 = 0.933, a normal r2 = 0.995, while the best Quantitative CoMFA-Separation Factor Relationship, also derived from the study, yielded a cross-validated q2 = 0.939, a normal r2 = 0.991. When all of these results are considered, this QSRR-CoMFA analysis appears to be a very useful tool for the preliminary prediction on the chromatographic behaviors of drugs with an amine moiety inside chiral CBH columns.
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Affiliation(s)
- Sun Ok Choi
- Division of Biopharmaceutics, Department of Pharmacology, National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul 122-704, Korea
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Abstract
Molecular Chirality is of central interest in biological studies because enantiomeric compounds, while indistinguishable by most inanimate systems, show profoundly different properties in biochemical environments. Enantioselective separation methods, based on the differential recognition of two optical isomers by a chiral selector, have been amply documented. Also, great effort has been directed towards a theoretical understanding of the fundamental mechanisms underlying the chiral recognition process. Here we report a comprehensive data examination of enantio separation measurements for over 72000 chiral selector-select and pairs from the chiral selection compendium CHIRBASE. The distribution of alpha = k'(D)/k'(L) values was found to follow a power law, equivalent to an exponential decay for chiral differential free energies. This observation is experimentally relevant in terms of the number of different individual or combinatorial selectors that need to be screened in order to observe alpha values higher than a preset minimum. A string model for enantiorecognition (SMED) formalism is proposed to account for this observation on the basis of an extended Ogston three-point interaction model. Partially overlapping molecular interaction domains are analyzed in terms of a string complementarity model for ligand-receptor complementarity. The results suggest that chiral selection statistics may be interpreted in terms of more general concepts related to biomolecular recognition.
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Affiliation(s)
- Ran Kafri
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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