CAPABILITY OF A CARBON SUPPORT TO IMPROVE THE GAS-CHROMATOGRAPHIC PERFORMANCE OF A LIQUID-CRYSTAL PHASE IN A PACKED-COLUMN FOR SOME VOLATILE OIL CONSTITUENTS

''Graphpac'' was investigated to see if carbon was a better gas chromatographic support than silica for columns of 3% of the liquid crystal bismethoxybenzilidinebitoluidine or (MBT)2. Six volatile oil component solutes exhibited the same elution sequence as from silica, but with lower relative retention times with respect to linalol -about 50% for some aromatics, reflecting the much lower polarity of the carbon-supported packing indicated by cuminal/caryophyllene ratio. Caryophyllene had greatly increased relative retention, and this was further raised if a low-loading of 0.3% (MBT)2 was used on ''Graphpac'', indicating even lower polarity. This column was not reliable below 200-degrees-C, but an initial period at 203-degrees-C, followed by rapid heating to 230-degrees-C, gave reasonable results for some significant constituents of teatree oil. Nevertheless, 3% (MBT)2 on ''Graphpac'' was preferable for assaying this and sweet fennel oil by providing a more reliable melted liquid crystal stationary phase, with low temperature versatility.