Molecular structural coefficients of Takács. Their dependence on column temperature, stationary phase polarity and solute chemical nature

1994 ◽  
Vol 38 (11-12) ◽  
pp. 701-708 ◽  
Author(s):  
J. M. Santiuste
Keyword(s):  
Stationary Phase ◽  
Chemical Nature ◽  
Column Temperature ◽  
Stationary Phase Polarity

A New Kind of Material for HPLC – Dioscin-Bonded Silica Gel Stationary Phase

2015 ◽  
Vol 723 ◽  
pp. 680-683
Author(s):  
Xin Yi Li ◽  
Xiao Juan Gu ◽  
Bao Chun Shen
Keyword(s):  
Stationary Phase ◽  
Silica Gel ◽  
High Performance ◽  
Panax Notoginseng ◽  
Active Pharmaceutical Ingredient ◽  
Reversed Phase ◽  
One Pot ◽  
Column Temperature ◽  
Hplc Fingerprint ◽  
New Stationary Phase

A new dioscin-bonded silica gel stationary phase with natural active ingredient for high performance liquid chromatography was prepared by one-pot reaction method, using 1,6-diisocyanate as the spacer arm. The structure of new stationary phase was characterized by solid-state NMR techniques, infrared spectroscopy, elemental analysis, thermogravimetric analysis and scanning electron microscope. These results show that the dioscin has been bonded to the silicia gel. The resulting stationary phase containes 127.6 μmol/g dioscin ligand. The chromatographic performance of this new stationary phase was evaluated by different kinds of solute probes. The results illustrate that the new stationary phase has a typical reversed phase chromatographic property, meanwhile it could present various interactions with solutes. The HPLC fingerprint of PNS(Panax Notoginseng saponins) API(active pharmaceutical ingredient) on the dioscin-bonded silica gel stationary phase was established. The mobile phase was consisted of gradient acetonitrile and water. The detection wavelength was 203 nm, the column temperature was maintained at 35 degrees Celsius, the flow rate was 0.8ml/min and the injection volumn was 15 μL. The contents of the 5 co-possessing components were determined simultaneously. A new material for HPLC was made by natural product. The using of dioscin-bonded silica gel stationary phase provides a new idea in natural products research.

scholarly journals Liquid chromatographic enantioseparation of thalidomide and its derivatives on cyclodextrin-bonded stationary phases

2018 ◽  
Vol 91 (2) ◽  
pp. 99-106
Author(s):  
Szabó-Zoltán István ◽  
Foroughbakhshfasaei Mohammadhassan ◽  
Dobó Máté ◽  
Noszál Béla ◽  
Tóth Gergő
Keyword(s):  
Acetic Acid ◽  
Stationary Phase ◽  
Flow Rate ◽  
Chiral Separation ◽  
Stationary Phases ◽  
Reversed Phase ◽  
Chiral Separations ◽  
Column Temperature ◽  
Bonded Stationary Phases ◽  
Chiral Interactions

Abstract The chiral separation of three racemic immunomodulatory drugs, thalidomide, pomalidomide and lenalidomide was studied, using three cyclodextrin bonded stationary phases (β-, hydroxypropyl-β- and carboxymethyl-β-CD) in reversed-phase and polar organic mode. In polar organic mode, using acetonitrile and methanol, no chiral separation was observed. In reversed-phase mode pomalidomide showed chiral interactions with all selectors, while lenalidomide showed no chiral interactions with any of the cyclodextrins employed. Thalidomide showed chiral interactions with β-and carboxymethyl-β-CD, only. Based on these observations it can be concluded that the oxo group at position two is necessary for chiral recognition, while the aromatic primary amine group enhances it. Orthogonal experimental design was used to investigate the effect of the eluent composition, flow rate, and the column temperature on chiral separation. Concentration of the organic modifier was the most important factor among the investigated three variables showing high impact on the chiral separations. In the case of thalidomide optimized parameters (β-cyclodextrin-based stationary phase, 0.1% acetic acid/acetonitrile 95/5 (v/v), 5 °C column temperature, 0.6 ml/min flow rate) resulted in a resolution of 1.68 ± 0.02 between enantiomers. For pomalidomide, this value was 2.70 ± 0.02, under the circumstances as follows: β-cyclodextrin-based stationary phase, 0.1% acetic acid/acetonitrile 90/10 (v/v), 15 °C column temperature and 0.8 mL/min flow rate. Utilizing the experimental conditions employed on an LC-MS/MS system, concentrations as low as 2 ng/mL could be determined from mouse plasma for both substances. Elution sequences were determined with enantiopure standards and in both cases the R-enantiomers eluted first. The methods developed are suitable for the chiral separation of the abovementioned compounds and are sound starting points for bioanalytical method development.

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