BACKBONE MODIFICATION OF CHIRASIL-VAL .1. EFFECT OF LOADING ON THE SEPARATION OF ENANTIOMERS BY GAS-CHROMATOGRAPHY

For the gas chromatographic phase Chirasil-Val, the effect of loading of the polysiloxane backbone with L-valine tert.-butylamide units on t he chromatographic properties is described. For three enantiomeric pai rs of N-trifluoroacetyl amino acid n-propyl esters, a maximum separati on factor (alpha) was observed when the ratio x:y of x dimethylsiloxan e units per y chirally modified dialkyl siloxane units was adjusted to the range of x:y = 5.6-5.9; whereas a ratio x:y = 7 has proven more s uitable for the complete separation of all 39 components present in a mixture of the 20 proteinogenic amino acids.