Chemotyping Cannabis by Spectral Fingerprinting
Cannabis is a burgeoning industry worldwide both for medicinal, esthetic, and recreational products. Because Cannabis species are polymorphic many hybrids are available with different properties. In addition, the growing and harvesting conditions of cultivars may also have a pronounced effect on the properties of Cannabis products, which may be available in a variety of forms, such as buds, leaves, powders, oils, tinctures, edibles, and extracts. Chemotyping refers to the classification of materials based on their overall chemical composition. It provides a method for characterizing variable botanical products such as Cannabis by their overall chemical composition. Genotyping refers to characterizing materials based on their genetic traits, but only indirectly relates to the chemical composition and for some products, the genetic material may be degraded or absent. Another form of characterization is by morphology, but again morphology only indirectly characterizes the chemical composition of the plant material and is useless when the morphology is destroyed in a powder or an extract. Using spectroscopy, the overall chemical composition may be measured rapidly and can be automated. For this fingerprinting approach, only the shape of the spectrum is used so no standards are required. Chemometric models are built from the spectra that can be used to authenticate and characterize the pharmacological and organoleptic properties of Cannabis products. In one example, we use an ultraviolet microplate reader (UVMR) as a high-throughput device to characterize Cannabis extracts. UVMR is a low cost and high-throughput device that could be used in the cannabis industry for assaying and authenticating botanical ingredients. Low-quality, decomposed, or adulterated products would be detected using this affordable approach.
Professor Peter de B. Harrington, Director, Ohio University Center for Intelligent Chemical Instrumentation was speaking at The Science of Cannabis Online Symposium 2018.