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Other Quantifiable Tests for Testing the Quality and Purity of Essential Oils

Other tests may be used upon an essential oils. The most commonly used tests after Gas Chromatography and Mass Spectrometry are Refractive Index and Specific Gravity. The results of these tests are sometimes provided upon the oil's MSDS (Material Safety Data Sheet).

Refractive Index

Measured by a refractrometer, the refractive index of an essential oil is a unique number that designates how the oil responds and bends light. Essentially, it is a measurement that tests how the speed of light is altered when passing through the oil. An oil's refractive index can be compared to that of a reliable sample.

Specific Gravity

Measured using a densitometer, the specific gravity of an essential oil is a unique number that measures the density of a particular oil in comparison with the density of water. Specific gravity readings are measured at precise temperatures and pressures as temperature and pressure can impact the measurements. Particular oils have known ranges of specific gravity in which the oil is considered to be unadulterated and pure. Of course, an essential oil distilled from an inferior harvest or improperly distilled can also lead to specific gravity readings outside the norm.


Other possible Tests that May be Conducted On Essential Oils Include the Following

  • Optical Rotation
  • Acid Value
  • Infrared Spectroscopy


This topic consists of several separate related articles. Use the links shown below to navigate through the series.

Next: Part 10: Essential Oil Quality and Purity Conclusion: Final Questions/Answers

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