EVALUATION OF A CHIRASIL-VAL CAPILLARY FOR THE GAS-CHROMATOGRAPHY OF VOLATILE OIL CONSTITUENTS, INCLUDING SESQUITERPENES IN PATCHOULI OIL

The methyl-polysiloxane phase ''Chirasil-Val'' containing about 6% branched aliphatic side chains with L-valine in diamide linkage, has had its response assessed to various volatile oil constituents. Changes in relative retention times with temperature increase were distinctively large for camphor and fenchone. There was a greater spread of retention indices for seven solutes than on fully methyl polysiloxane, although less difference for another three solutes. Isothermally at 130 degrees C, Chirasil-Val gave better resolution of the sesquiterpene hydrocarbon mix in patchouli oil than methyl polysiloxane, and could then be temperature programmed to evaluate patchoulol, etc. Carbowax 20M is a poor phase for patchouli analysis.