ENANTIOSEPERATION OF NEW CHIRAL HYDANTOIN DERIVATIVES IN HIGH PERFORMANCE LIQUID CHROMATOGRAPHY USING POLYSACCHARIDE-BASED STATIONARY PHASES

Author: Ana Rakviashvili
Keywords: Chromatography, Enantiomers, Hydantoins
Annotation:

The main goal of the present study was to study a separation of enantiomers of structurally related chiral hydantoin derivatives in high-performance liquid chromatography using polysaccharide-based chiral columns with normal-phase and polar-organic mobile phases. As mobile phases acetonitrile, methanol and mixtures of n-hexane and propan-2-ol with various ratios were used. For the experiment hydantoin derivatives were chosen. They are interesting compounds in terms of their pharmacological activity. Different studies have demonstrated their antiepileptic, antiarrhythmic, antidiabetic and other properties. Dependence of retention of enantiomers and their separation on the structure of chiral compounds was studied. On the other hand, the effect of a structure of a chiral selector on its chiral recognition ability was evaluated. In addition, the enantiomer elution order of enantiomers was followed and several interesting examples of enantiomer elution order reversal based on the structure of chiral selector were observed. We also did calculation of thermodynamic parameters of enantioseparation of hydantoins in high-performance liquid chromatography. For analyzed compounds, the molar values of adsorption enthalpy and adsorption entropy, as well as their differences for enantiomers were calculated using the plot of natural logarithm of the retention and separation factors, respectively, versus the reciprocal of the absolute temperature. We studied if the enantioseparation mechanism was controlled by enthalpic or entropic term and what was the influence of temperature on retention and separation. In order to calculate thermodynamic parameters this experiment was conducted at different temperatures. We performed the analysis in the temperature range 5-65°C with 5° increments.