Effects of solvent on chiral and enantiomeric separation of Koga bases using derivatized amylose chiral stationary phase

Guo, Hong-Xun; Wu, Steven C.; Nadeau, Kelly; Moniz, George A.; Caille, Sebastian

doi:10.1002/chir.20704

Cited by 1 publication

(4 citation statements)

References 17 publications

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“…The retention factor and enantiomeric selectivity of Koga bases at different temperatures have been calculated and summarized in Table 1, Table 2, Table 3. The typical enantioseparation of Koga bases and chemical structures of Koga bases are shown in Figure 1 [4].…”

Section: Resultsmentioning

confidence: 99%

“…Chromatograms of R, R-; S, S; and meso-Koga base (chemical structure listed below) on a Chiralpak AD-H column, ---- Eluent: 85% -2-propanol-15% methanol-0.03% triethylamine, ----Eluent: 50% -2-propanol-50% methanol-0.03% triethylamine. Flow rate 0.25 mL/min at 20 °C and detection 215 nm [4]. …”

Section: Resultsmentioning

confidence: 99%

“…Although those studies satisfactorily account for the effect of temperature on the interaction between analyst and chiral stationary phase (CSP), limited information on the actual mechanism of the chiral separation process has been provided, and further work is needed in order to better understand the mechanism of chiral analytes’ selective retention on CSP. Koga bases were chosen for this study due to the fact that they contain two chiral centers that are C 2 -symmetric [3,4]. The thermodynamics and temperature effects on both enantiomeric and diastereomeric selectivity can therefore be evaluated.…”

Section: Introductionmentioning

confidence: 99%

“…To understand the aforementioned chiral separation phenomena, we have adopted a thermodynamic approach to analyzing chiral retention data obtained from Koga bases [3,4,12] on a polysaccharide phase (the AD-H [amylose tris-(3, 5-dimethylphenylcarbamate)] column) over a temperature range of 10 °C to 40 °C using two different polar organic eluent systems.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Temperature on the Enantioselectivity of Koga Tetraamines on Amylose Chiral Stationary Phases

Guo

Sun

2013

Molecules

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Enantioseparation is largely based on the formation of transitional complexes, the solvation species, the stationary phase configurations or the diastereomeric complexes formed by analytes and the chiral stationary phase. Temperature and the chemical nature and composition of the eluent play significant roles during that process. In this study; unique temperature-induced behaviors were observed during the enantioseparation of Koga tetraamines, also known as Koga bases, on polysaccharide chiral stationary phases, in which van't Hoff plots were acquired over a temperature range of 10 °C to 40 °C with 5 °C increments. Koga bases were eluted by a mixture of methanol and 2-propanol with 0.03% triethylamine as a modifier. The van't Hoff plots are linear in the case of eluent containing equal volumes of methanol and 2-propanol. Increasing 2-propanol concentration from 50% to 85% in volume led to non-linear van't Hoff plots over the entire temperature range studied. Examination of the individual non-linear plots revealed two linear regions of 10 °C-20 °C and 20 °C-40 °C. Transition from one linear region to the other at 20 °C indicates alterations of chiral stationary phase conformation and/or enantioseparation mechanism as a result of temperature changes.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%