MULTIDIMENSIONAL GAS-CHROMATOGRAPHY COUPLED WITH INFRARED AND MASS-SPECTROMETRY FOR ANALYSIS OF EUCALYPTUS ESSENTIAL OILS

A parallel cryogenic trapping multidimensional gas chromatography/Fourier transform infrared spectrometry/mass spectrometry combination (MDGC/FT-IR/MS) is evaluated for analysis of essential oils. As a demonstration of the value of this analytical approach, analyses of several essential oil samples are reported. The method developed to differentiate these oils is quite general and can be applied equally well to analysis of various other complex mixtures. By use of a multiport manual valve system in conjunction with multiple parallel cryogenic traps, it is demonstrated that three-stage or higher order gas chromatographic separations (GC(n)) are practical, providing the expected improvements in separation efficiency needed for accurate qualitative analysis. Chromatographic and spectroscopic data obtained by analysis of two authentic and one known adulterated Eucalyptus australiana oil samples are utilized as benchmarks for analysis of a fourth sample which is suspected of being adulterated and a fifth sample from an unknown source. It is concluded that the presence of either camphor or a combination of alpha-thujene, decane, sabinene, beta-phellandrene, and gamma-terpinene is indicative of eucalyptus oil adulteration.