Cannabis analysis: Determining the geographical origin and potency of cannabis plants, and investigating a novel method of cannabis oil manufacture

Abstract

Cannabis has a long history in the world as a plant with agricultural and medicinal value. However, the prohibition of cannabis began when it was listed under the 1925 Opium convention by the League of Nations currently known as the United Nations. Despite attempts to prohibit cannabis, coming into the 21st century, countries around the world have begun to legalise its use for both medical and recreational purpose. This study was aimed at assessing the THC and CBD content of cannabis samples from three geographically distinct regions in New Zealand as well as cannabis samples from Samoa using Gas Chromatography-Flame Ionization Detector analysis. Furthermore, the collected cannabis samples were used to determine whether their origins can be distinguished using elemental profiles obtained by Inductively Coupled Plasma-Mass Spectrometry and Laser Ablation- Inductively Coupled Plasma-Mass Spectrometry. Lastly, a novel method in the manufacture of cannabis oil in New Zealand using a petroleum-based solvent called Fuelite as opposed to isopropanol was assessed. Furthermore, using heat during the extraction was also assessed whether a change in yield would be observed. The results from the experiments carried out on the cannabis samples showed that the majority of the cannabis samples had a higher THC content than its CBD content. Female flowering cannabis samples from police casework are also presented. Using their THC and CBD content, the chemotypes of the cannabis samples were also assessed. Using principal component analysis and linear discriminant analysis, the elemental profiles of these cannabis plants were then statistically evaluated and their respective regions of origin were correctly identified. Lastly, the results from using Fuelite as an extraction solvent showed it was also possible to determine the extraction solvent used in the manufacture of the cannabis oil using Fourier transform infrared spectroscopy of the headspace from the damp cannabis plant material used in the manufacturing process. Furthermore, Gas Chromatography- Mass Spectroscopy analysis of the extracts from confirmed the presence of THC however harmful residual hydrocarbons were present in the extract which used Fuelite, which were not present in extracts carried out using isopropanol. It was difficult to determine whether there was a change in yield when heat was used during the extraction process due to variability in the results.