Traditionally, the choice of acid/base additives used in chiral preparative chromatography has not been considered very important. However, it was recently demonstrated that strongly adsorbing additives can result in the most unexpected enantiomer band shapes in modern chiral preparative chromatographic systems. In the present study we demonstrate that, depending on the choice of additive, it is actually possible to obtain the following four binary band-shape compositions when a racemic mixture is injected: (i) anti-Langmuir/anti-Langmuir, (ii) anti-Langmuir/Langmuir, (iii) Langmuir/Langmuir and (iv) Langmuir/anti-Langmuir. Further, we made an advanced numerical investigation, in order to ascertain which one of the four band-shape compositions, is the most favourable one in preparative batch chromatography of a racemic mixture. We found that if the target for purification is either the first eluting enantiomer or both ones, the traditional Langmuir/Langmuir band-shape composition should be chosen. But, if only the second eluting enantiomer is to be purified the optimal situation is the anti-Langmuir/Langmuir band-shape composition. Thus, it was concluded that the best choice of additive depends on which enantiomer is of interest and it is useful to perform a thorough additive screening to find the optimal additive, giving the most advantageous peak shape composition and accordingly the best process performance for a particular separation problem.
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http://dx.doi.org/10.1016/j.chroma.2009.04.010 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
() infections are increasingly challenging due to their propensity to form biofilms and low outer membrane permeability, especially in chronically infected patients with thick mucus. exhibits multiple drug resistance mechanisms, making it one of the most significant global public health threats. In this study, we found that moxifloxacin (MXC) and antibacterial peptides (ε-poly-l-lysine, ε-PLL) exhibited a synergistic effect against multidrug-resistant (MDR-).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Shandong University, Department of Chemistry, 27 South Shanda Road, 250100, Jinan, CHINA.
Planar chirality found tremendous use in many fields, such as chemistry, optics, and materials science. In particular, planar chiral [2.2]paracyclophanes (PCPs) are a type of structurally interesting and practically useful chiral compounds bearing unique electronic and photophysical properties and thus have been widely used in π-stacking polymers, organic luminescent materials, and as a valuable toolbox for developing chiral ligands or organocatalysts.
View Article and Find Full Text PDFAnal Methods
January 2025
Istanbul University, Faculty of Pharmacy, Department of Analytical Chemistry, 34116, Istanbul, Turkey.
In this study, a new reversed phase high performance liquid chromatography method using two detectors was developed for the analysis of degradation and process impurities of ivabradine in pharmaceutical preparations. A PDA detector set to 285 nm wavelength and a QDa detector set to positive scan mode were used in the method. In the developed method, the separation process was carried out in a Zorbax phenyl column with a gradient application of a 0.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Zhejiang University, Chemistry, Department of Chemistry, ZhiJinGang Campus, 310058, Hangzhou, CHINA.
Integrating two or more materials to construct membranes with heterogeneous pore structures is an effective strategy for enhancing separation performance. Regularly arranging these heterogeneous pores can significantly optimize the combined effect of the introduced components. Porous Organic Cages (POCs), an emerging subclass of porous materials composed of discrete molecules, assemble to form interconnected pores and exhibit permanent porosity in the solid state.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 Zhongguancun South Street, Beijing, 100081, China. Electronic address:
Background: The metal organic cages (MOCs) are an emerging type of porous material that has attracted considerable research interest due to their unique properties, including good stability and well-defined intrinsic cavities. The chiral MOCs with porous structures have broad application prospects in enantiomeric recognition and separation. However, there are almost no relevant reports on chiral MOCs as chiral stationary phases (CSPs) for enantioseparation by high-performance liquid chromatography (HPLC).
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