How to Test Essential Oils for Purity

Here you can get How to Test Essential Oils for Purity. Essential oils are growing in popularity due to their pleasant scents and various household uses.

However, the purity of the volatile oil is vital for creating sure it’s as effective as possible. To verify that your essential oils are top quality , it’s important that you simply learn the signs of an honest volatile oil and test the oils out for yourself.

Confirming Identity & Purity

NOW regularly assesses the standard of our essential oils through the evaluation of purity and identity. This protects our retailers and consumers, ensuring they get the merchandise they purchased .

We utilize numerous physical or physiochemical techniques, including:

  • Instrumental testing like index of refraction , Optical Rotation, relative density , Gas Chromatography (GC), and Inductively Coupled Mass Spectrometry (ICP-MS);
  • And, Organoleptic Evaluation, that specialize in appearance and odor.

Instrumental Testing: Refractive Index

The measurement of refraction of sunshine rays as they undergo material. This test is performed with the assistance of a refractometer. a couple of drops of an oil under test are put between 2 prisms of the instrument at a known temperature and therefore the index is measured. This testing thus requires little or no sample and time; however, index of refraction is merely a qualitative test of purity of essential oils.

Instrumental Testing: Optical Rotation

Whenever light rays undergo a transparent material, additionally to refraction, rotation of plane of polarization also can occur. this is often referred to as Optical Rotation and is defined as a degree of angle of rotation. This rotation are often to the left (levo rotatory or minus) or to the proper (dextro rotatory or plus). The instrument wont to determine optical rotation is named a polarimeter.

It measures the degree of rotation by passing monochromatic light through the primary of two polarizing plates, creating a polarized beam. This beam is then rotated because it passes through the sample. After passing through the sample, a second polarizer (analyzer) rotates. When the analyzer is rotated such all the sunshine or no light can undergo , the angle of rotation is decided . Optical rotation, similarly to index of refraction , may be a qualitative measure of the purity of oils.

Instrumental Testing: Specific Gravity

Important in determining the standard and purity of an important oil, the technique could also be explained because the ratio of the load of a selected volume to the load of an equal volume of water at an outlined temperature. the precise gravity of water is 1. so as to work out relative density of a sample, approximately 10 mL of volatile oil is added to a tube and submitted for analysis using an automatic density meter, which determines the load of the sample at a selected temperature. relative density of the oil is inversely proportional to the temperature, therefore the temperature plays a critical role during this determination. Our instrument is capable of adjusting the pre-set temperature with an accuracy right down to ± 0.01°C.

Instrumental Testing: Gas Chromatography (GC)

Gas chromatography (GC) has been a key tool in characterization and purity evaluation of essential oils. The principle of GC operation is chromatographical separation of volatile components of the volatile oil into individual peaks to make a singular , fingerprint-like, chemical composition profile. Mass Spectrometry (MS) detector allows identification of every of those components using their nominal masses and determines their percentages.

The GC-MS component profile does indicate whether an oil is from the right genus/species, of inferior quality, or if it’s adulterated or contaminated with other, less costly essential oils, fragrance compounds, plasticizers, or other unwanted components. NOW® utilizes a specialized third-party testing laboratory to perform the GC-MS testing of essential oils because it continues to create an in-house testing program for the analysis of essential oils by GC-MS. But we go further than that. NOW®’s in-house testing program also will employ a statistical analysis approach using the GC-MS data to guage the identity, purity, and therefore the natural disparity of the essential oils to further control the standard of our products.

Instrumental Testing: Inductively Coupled Mass Spectrometry (ICP-MS)

Essential oils are often easily contaminated with heavy metals from the environment (soil, water, or air) during plant growth and therefore the manufacturing processes. to make sure that NOW® essential oils aren’t contaminated with toxic levels of arsenic, cadmium, lead and mercury, we employ ICP-MS analysis. In short, essential oils are digested employing a strong acid and introduced into a hot plasma (burning argon gas), which ionizes the weather . The heavy metals are then detected and quantified at nanogram levels by the spectrometer.

Pesticide Residue Analysis

The widespread use of pesticides on botanicals may result in residues present in essential oils, whether or not they are produced by cold pressing, steam distillation, or solvent extraction. Pesticide residues are often co-extracted, and thanks to essential oils being very concentrated, they could be present within the oils at high concentrations. At NOW®, we’ve developed an in-house pesticide residue testing program, allowing us to watch the potential pesticide contamination in our essential oils. The broad spectrum of pesticides tested between two analytical platforms, Liquid Chromatograph Tandem spectrometer (LC-MS/MS) and Gas Chromatograph Tandem spectrometer (GC-MS/MS) further guarantees the standard of our products.

Organoleptic Evaluation – Focusing on Appearance and Odor

The nose is one among the foremost efficient tools in volatile oil sensory evaluation. A trained volatile oil analyst can notice even small differences in odors and may immediately detect a top quality problem with an oil before proceeding with more sophisticated analytical tests. an important oil are often rejected supported a poor or uncharacteristic odor profile. Although there are many advancements within the analytical techniques, organoleptic evaluation can still be the only most vital arbiter of volatile oil quality when a seasoned, trained volatile oil chemist is making the decision.


  • Essential oils should never be ingested unless you’re under the care of a trained professional.
  • If you’re doing home testing on your oils, confirm you’re working during a space that’s well-ventilated to stop overwhelming or unpleasant scents.
  • If you’re unsure about the standard of an important oil, hold off on buying it until you’re ready to verify that it’s pure.
How to Test Essential Oils for Purity

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