Ensuring the quality of CBD oil

23 May 2022

Scientists develop a simple and useful method for measuring the concentration of cannabidiol (CBD) and convertible THC in CBD oil.

Extracts of Cannabis sativa L. are highly complex, containing more than 100 naturally-occurring active cannabinoids. The two most important compounds are the psychoactive delta-9-tetrahydrocannabinol (THC) - and the non-psychoactive cannabidiol (CBD), which is growing in popularity as a natural remedy for many common ailments.

CBD is widely sold over-the-counter in the form of concentrated oils, food supplements, cosmetics and electronic cigarettes. In Japan, CBD-containing products are not widely available in general stores but are sold over the internet marketed to relieve symptoms of conditions such as chronic pain or anxiety.

CBD products, such as hemp seed oil, are often imported from the US and other countries – and are assessed for illegal THC and impurities before reaching the Japanese marketplace. However, as these could potentially degrade over time depending on their storage conditions, there is a need to develop more rigorous methods for monitoring CBD oils – including measuring convertible THC under acidic conditions.

Identifying counterfeit products

In a new study, published in Chemical and Pharmaceutical Bulletin, researchers apply a routine assay to profile CBD, THC and other cannabinoids – and convertible THC – in hemp seed oil products sold on the Japanese market.¹

The researchers used liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) to profile six selected chemicals: cannabidiolic acid (CBDA), cannabigeriolic acid (CBGA), cannabigerol (CBG), CBD, THC and cannabinol. The oil samples were diluted with isopropanol, followed by the addition of stable isotope internal standards by dilution with methanol/water, with accuracy rates ranging from 97.8 to 102.2%.

The team applied the LC-MS/MS assay to evaluate five CBD oil products from the Japanese market, identifying one obvious counterfeit product containing no detectable CBD. They then measured convertible THC under simple conditions (such as 10% acetic acid for six hours at 70^oC) – discovering that the convertible THC proportions were approximately <1%, or about 5%, across the five products.

The researchers used purified water generated from an ELGA PURELAB® Flex 5 water purification system, minimising the risk of adding contaminants that could affect their results.

Quality assurance

In this study, researchers developed an LC-MS/MS assay for cannabidiol profiling in CBD oil available on the Japanese market. Their survey of five hemp seed oils identified one counterfeit product containing no detectable CBD, but reassuringly, none contained any THC.

In addition, they also found that the minuscule quantities of convertible THC and other cannabinoids from CBD oil in acetic acid conditions at high temperatures could be separated and detected using the method.

The researchers conclude that applying this chemical reaction to convert THC from CBD oil is too inefficient for abusable use. But it may be possible to use this method to apply a tough decision about whether deteriorated CBD oils and/or various other products can claim to contain ‘no detectable THC.’

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Reference:

1. Takashina, S. et al. LC-MS/MS Assay for the Measurement of Cannabidiol Profiling in CBD Oil from Japanese Market and Application for Convertible Tetrahydrocannabinol in Acetic Acid Condition. Chem. Pharm. Bull. 2022;70:169-174.