Physiochemical Testing of Essential Oils- Part 2- Gas Chromatography/Mass Spectrometer

7:01 AM Posted by jo

This is part two in the series about physiochemical testing.

Gas Chromatography, GC, test will separate the different constituents in the essential oils based on the different  molecular weight and solubility. The GC test identifies the relative quantities and the presence of chemical constituents, but it is impossible to identify the specific constituents without the mass spectrometry test.

In order to carry out a GC test the essential oils needs to be put into the injection chamber. After the oil has vaporized in the injection chamber, helium will transport it to a column where it will enter a stationary phase. The amount of time it takes through the stationary phase is very individual. Now the molecules separate and are transferred to the vacuum ionization chamber. Since the gas chromatography only shows the relative concentration of chemical compounds, it is now beneficial to perform a mass spectrometry test. The MS test is done to identify each individual peak of the Gas Chromatography.

In a Mass Spectrometry molecules or particles are electrically charged, which is known as being ionized. The accelerated ions are separated according to their mass-to-charge ratio. The Mass Spectrometry is performed by a spectrometer, which can determine the molecular weight by measuring the negative and positive ion currents. The results can be read graphically or as a computer output. Even though GC/MS identifies and quantifies the different constituents. It can not detect if oil is diluted with synthetic or natural dilutants. It can detect if the oil is a mixture of oils with similar composition, if the oil is rectified, if it contains traces of minerals, and if the terpenes have been removed.

Testing oils for quality and purity is costly and time consuming, but it is a very important step in aromatherapy. We need to be able to trust the oils we use sine adulterated essential oils may be harmful or even have different therapeutic actions.


Johanna is an aromatherapist and she is passionate about educating people about health, essential oils, real food, natural remedies, and nutrition so they make healthier choices in their lives.
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