Gas chromatography: Gas chromatography relies on the fact that the different chemical constituents of an essential oil will move through a column containing an inert or carrier gas at different rates. The resulting printout contains a number of peaks, with each peak linked to a particular chemical constituent of the oil. Gas chromatography is one of the most useful, modern methods of analysing essential oils. For an example roll over the chromatography print out to see the difference between a cheap and a reputable oil.

Smell: An experienced aromatherapist can develop their sense of smell to the point that it is a useful tool in establishing quality of oils. This can be enhanced by comparing the smell to a standard oil of known quality.

Essential oils are usually complicated mixtures of chemicals and the level of testing required to establish exact quality of supplies would result in the oil being prohibitively expensive. Reputable suppliers should provide data sheets for oils with results of tests such as those outlined above but the most effective method to ensure quality is to monitor the growth and extraction of the oils. Suppliers should be able to provide details of how this is done.

Gas chromotography graph of pure lavender essential oil
(Rollover for gas chromotography graph a cheaper non - essential oil)