Authors:H. Dong, Y. Wang, Y. Ou, J. She, X. Shen, J. Li, C. Zhang, and L. Liu
Molecularly imprinted polymers (MIPs) were synthesized by imprinting a new template—S(-)-1,1′-binaphthalene-2,2′-diamine (S-DABN) and applied as chiral stationary phases for chiral separation of DABN racemates by high-performance liquid chromatography (HPLC). The influence of some key factors on the chiral recognition ability of MIPs, such as the type of functional monomers and porogen and the molar ratio of template to monomer, was systematically investigated. The chromatographic conditions, such as mobile phase composition, sample loading, and flow rate, were also measured. The chiral separation for DABN racemates under the optimum chromatographic conditions by using MIP chiral stationary phase (CSP) of P3, prepared with the S-DABN/MAA ratio = 1/4 and used acetonitrile (2 mL) and chloroform (4 mL) as porogen, showed the highest separation factor (2.14). Frontal analysis was used to evaluate affinity to the target molecule of MIPs. The binding sites (Bt) of MIPs and dissociation constant (Kd) were estimated as 4.56 μmol g−1 and 1.40 mmol L−1, respectively. In comparison with the previous studies, this approach had the advantages, such as the higher separation factor, easy preparation, and cost-effectiveness, it not only has the value for research but also has a potential in industrial application.
Authors:G. Barone, G. Castronuovo, V. Elia, and C. Giancola
The heats of dilution in water of binary and ternary solutions of the two enantiomeric forms ofN-acetylalanineamide have been measured at 25°. The excess enthalpies, expressed as virial expansion series, permit evaluation of the pairwise self and cross enthalpic coefficients. As for the chiral forms of some monosaccharides, the cross coefficient for the interaction between theD andL forms ofN-acetylalanineamide is slightly but significantly different from the corresponding self coefficient. A weak, water-mediated chiral recognition can be assumed to exist between pairs of amide molecules.
In order to reveal the origin of chiral discrimination, excess molar heat capacities (CPE) of ((R)-(+)-limonene+(S)-(−)-limonene) were determined by using a differential scanning calorimeter at temperatures between T=293.15 and 303.15 K. All CPE curves show S-shape. It was inferred that randomness appears in the (S)-(-)-limonene-rich region, and that non-randomness
appears in the (R)-(+)-limonene-rich region. To clarify the differences in homochiral interactions and heterochiral interactions, molecular
orbital calculations were carried out.
Authors:M. Matthews, I. Atkinson, Lubaina Presswala, O. Najjar, Nadine Gerhardstein, R. Wei, Elizabeth Rye, and A. Riga
Dielectric analysis (DEA), supported by thermogravimetric analysis (TG), differential scanning calorimetry (DSC), powder X-ray
diffraction analysis (PXRD) and photomicrography, reveal the chiral difference in the amino acids. The acids are classified
as dielectric materials based on their structure, relating chirality to the vector sum of the average dipole moment, composed
of the constant optical (electronic) and infra-red (atomic) polarizabilities, as well as dipole orientation. This study encompasses
14 L-and D-amino acid isomers. Physical properties recorded include AC electrical conductivity, charge transfer complexes, melting,
recrystallization, amorphous and crystalline phases, and relaxation spectra, activation energies and polarization times for
the electrical charging process.
-globulin glycoprotein, and peptide moieties from MGs like teicoplanin aglycone, vancomycin, and Ristocetin A are covalently bonded to high purity 5 μm silica while retaining stability and essential components for chiralrecognition. The immobilization of α1-acid
Authors:M. Koźbiał, J. Poznański, E. Utzig, and J. Lipkowski
formation of D-mannonaphto-18-crown-6-ether
1 with D- and L-phenylalanine
(Phe) and their derivatives was studied using conduction and titration microcalorimetry
in aqueous solution, and solvent–solvent (water–chloroform) extraction.
The thermal effects accompanying the complexation process were determined,
but the chiral recognition effects were very small. The chiral differentiation
of amino acid was observed in the experiments of the extraction from water
to chloroform phase containing chiral receptor.
Authors:Sahrish Khatri, Najma Memon, Zeeshan Khatri, and Farooq Ahmed
, and non-woven fiber mats onto an alumina sheet. The sheets showed excellent chiralrecognition for histidine and serine isomers as a stationary phase in their TLC separation. These TLC sheets showed potential to be studied further and can be used as a