Validating a gas chromatography-mass spectrometric method and sample classification procedure for cannabis profiling using cannabinoids from case samples

A gas chromatography–mass spectrometric (GC–MS) method was evaluated for cannabis profiling. Method validation was carried out using four cannabinoids extracted from cannabis case samples. In the presence of the sample matrix, the instrument was able to achieve repeatability and reproducibility with relative standard deviation (RSD) values ≤ 10.99% and ≤ 9.09%, respectively. The MS detector also produced a linear response for each of the target cannabinoids with R² values ranging from 0.976 to 1.000. The method was found to be accurate as it displayed satisfactory recoveries (assessed based on the percentage difference between the measured amount and the expected or calculated amount of the analyte) between –11.35% and 0.96% for the difference. Subsequently, five different batches/groups of cannabis plants that were assumed to have come from different sources were tentatively used to assess the sample classification outcome. These samples were correctly clustered on a dendrogram with 12% errors. Through this preliminary study, it is deduced that cannabis samples could be profiled to estimate their source level relationships by using the proposed GC–MS method.