APPLICATION OF GAS-LIQUID-CHROMATOGRAPHY TO THE ANALYSIS OF ESSENTIALOILS .17. FINGERPRINTING OF ESSENTIAL OILS BY TEMPERATURE-PROGRAMMED GAS-LIQUID-CHROMATOGRAPHY USING CAPILLARY COLUMNS WITH NONPOLAR STATIONARY PHASES

Problems in obtaining reproducible results when 'fingerprinting' essen tial oils by temperature-programmed gas-liquid chromatography have bee n reported on in Parts VII and VIII of this series. Those reports were concerned with the general problems and the use of packed columns. Th is report is concerned with the use of capillary columns and non-polar stationary phases. A collaborative study using capillary columns with non-polar stationary phases has resulted in a method which specifies the 'g-pack value' of a column and gives reproducible relative retenti on indices for the test compounds limonene, acetophenone, linalol, nap hthalene, linalyl acetate and cinnamyl alcohol. The method has been ap plied successfully to the examination of oil of rosemary, A recommende d method is given for the reproducible temperature-programmed gas-liqu id chromatographic fingerprinting of essential oils using capillary co lumns with non-polar stationary phases.