Photoacoustic studies of the vapors of the essential oils of thyme, mint and anise have been made using a line-tunable waveguide CO$-2$/ laser in conjunction with a heat-pipe type of photoacoustic vapor sample cell operated over the temperature range 20 - 180$DGR@C. Identifying spectral fingerprint features are found in the 9 - 10 $mu@m spectral region for each of the three essential oils investigated. The principal features of the photoacoustic spectrum of each essential oil are associated with the dominant chemicals present i.e. thymol in thyme oil, menthol in mint and anethole in anise.
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