The separation of amino acid enatiomers on optically active dipeptide carborane stationary phases

Summary N-Trifluoroacetyl (TFA) dipeptide-o-carboranyl propyl esters of L-valyl-L-valine and L--amino-n-butyryl-L--amino-n-butyric acid have been prepared and the properties of these two new stationary phases for the gas-liquid chromatographic sepaation of amino acid enantiomers have been examined. It was found that the amino acid derivatives have shorter retention times, while maintaining good separation factors, on these carborane phases as compared to other dipeptide stationary phases. Both high and low boiling derivatives have been resolved on a 165 m×0.5 mm capillary column. The new phases have greater thermal stability and can be utilized over a wide temperature range.