Effect of temperature on the reversal in the retention order of the enantiomers of mosapride on Chiral-AGP.
The retention order of the enantiomers of mosapride could be controlled by column temperature and mobile phase pH. In the presented paper, temperature studies have been used to study the thermodynamics of the reversal in retention order. A linear relationship was obtained plotting the logarithm of the capacity factor versus the inverted column temperature. However, at higher mobile phase pHs, the logarithm of the separation factor versus the inverted column temperature showed a non-linear behaviour and at the highest mobile phase pH used (pH=7.4), an optimum in the separation factor was observed. The plots showed that the thermodynamics for the two enantiomers of mosapride differ in the studied mobile phase pH interval. Thermodynamic values, enthalpy and entropy were calculated and showed that at a low mobile phase pH, the enantiomeric resolution was caused by differences in enthalpy between the two enantiomers. However, at a higher mobile phase pH, the chiral discrimination was a result of entropy effects. High correlation was obtained between experimental and predicted separation factors at different mobile phase pHs.
Karlsson
Anders
A
Analytical Chemistry, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden. anders.AS.karlsson@astrazeneca.com
Skoog
Anette
A
Ohlén
Kristina
K
D001549:Benzamides / Q000032:analysis / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification*; D002853:Chromatography, Liquid / Q000379:methods*; D003198:Computer Simulation; D004735:Energy Transfer; D019277:Entropy; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D009025:Morpholines / Q000032:analysis / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification*; D009961:Orosomucoid; D012680:Sensitivity and Specificity; D013237:Stereoisomerism; D013696:Temperature
D001549:Benzamides; D009025:Morpholines; D009961:Orosomucoid; C062720:mosapride