Quantifiable Testing of Essential Oils for Quality and Purity
Several quantifiable tests exist that allow scientists, producers, suppliers and end users to be able to test their oils to determine quality and help to ascertain if an oil is pure and of the quality sought after for each particular botanical.
Gas Chromatography and Mass Spectrometry (GC-MS) or Flame Ionization Detection (GC-FID)
Testing by means of GC-MS or GC-FID can help to verify that the constituents contained within an essential oil sample are representative of what that particular essential oil should contain.
Gas Chromatography is conducted and then either Mass Spectrometry or Flame Ionization Detection are separate tests that are conducted to identify the constituents present in th essential oil. Mass Spectrometry or Flame Ionization Detection assists in identification of the specific constituents seperated within Gas Chromatography, so typically, the tests are done together.
Gas Chromatography
Gas Chromatography, also known as Gas Liquid Chromatography is abbreviated as GC or sometimes GLC.
Gas Chromatography measures the constituents contained within a particular essential oil sample by plotting each constituent found within the sample onto a graph. To begin, a sample of the oil is placed into the heating chamber of the gas chromatograph machine. The oil sample is then heated to a specific temperature until the constituents vaporize. Each constituent vaporizes at a different rate of time. As each constituent vaporizes, is passes through a detector that measures a) the time it took for the constituent to vaporize and b) the percentage/concentration of the constituent within the particular sample.
The gas chromatograph machine plots a graph of the results. The x-axis identifies the time that passes between the vaporization of each constituent. The y-axis shows the percentage concentrations of each constituent within the oil.
Mass Spectrometry and Flame Ionization Detection
Mass Spectrometry or Flame Ionization Detection is used in conjunction with Gas Chromatography.
Each compound, after passing through the gas chromatograph machine, is then analyzed via either Mass Spectrometry or Flame Ionization Detection. The results are then charted in a table.
For more information about GC-MS vs. GC-FID testing, please read the next article within this guide.
Next: Part 7: GC-MS and GC-FID Test Results: How to Understand and Use Them
This topic consists of several separate related articles. Use the links shown below to navigate through the series.
- Part 1: Introduction
- Part 2: Why Is the Quality/Purity of an Essential Oil Important?
- Part 3: Aren't Most Essential Oils Pure?
- Part 4: Constituents - What do Essential Oils Consist Of?
- Part 5: Quality vs. Purity - Aren't They the Same Thing?
- Part 6: Quantifiable Testing of Essential Oils
- Part 7: GC-MS and GC-FID Test Results: How to Understand and Use Them
- Part 8: Organoleptic Testing of Essential Oils
- Part 9: Other Quantifiable Tests for Testing the Quality and Purity of Essential Oils
- Part 10: Essential Oil Quality and Purity Conclusion: Final Questions/Answers
