Investigation and Analysis of Naturally Occurring Cannabinoids

There has been a recent proliferation of edible consumer products containing Cannabidiol (CBD), which is a closely related molecule to Tetrahydrocannabinol (THC), both of which are found in cannabis plants. It is thought that any products containing CBD are likely to have a calming effect on the consumer without the psychoactive effect's THC tends to induce. Due to this growing market it is becoming increasingly important to establish an analytical method which can quantify these substances and differentiate between them, as THC is a regulated compound.

Both CBD and THC can exist in acid form, CBDA and THCA respectively, which make such analyses challenging. A further complication is that certain analytical techniques such as GC, with high temperature at the inlet, can cause decarboxylation of the CBDA/THCA to CBD/THC.

In this project, use of NMR to initially identify and then assess purity of compound standards, was then followed up with method development of liquid chromatography - mass spectrometry (LC-MS) and gas chromatography - mass spectrometry (GC-MS) instruments to further identify and then quantify any cannabinoids present. A method was then developed for detecting and quantifying the presence of cannabinoids within foodstuffs labelled as containing CBD using the developed methods.

Qualitative results of investigations were consistent between GC-MS and LC-MC instruments suggesting these are reliable, but quantification optimisation on the methods is needed in future. Due to the lower temperatures used in the LC-MS, reducing decarboxylation reactions within the instrument, this allowed for the a more successful method to detect and identify cannabinoids regardless of acid form present to be achieved.