Walter Brent Wilson* | National Institute of Standards and Technology (NIST) Abstract: Forensic laboratories have been forced to start differentiating seized Cannabis products as either legal hemp or illegal marijuana in many parts of the United States after the passage of the 2018 Farm Bill. In 2021, hemp production in the United States was worth an estimated $824M with approximately 76% focused on floral hemp that is used to produce hemp-derived finished products such as smokable plant products, vape cartridges, oils, or edibles.1 Historically, forensic laboratories have only performed a series of qualitative measurements: macro- and microscopic identification of plant features, colorimetric test for presence of tetrahydrocannabinol (THC), and confirmation of Δ9-THC by gas chromatography-mass spectrometry (GC/MS). With new legislation, forensic laboratories are now required to quantify the level of total Δ9-THC in seized evidence to distinguish them as either hemp or marijuana products. In response, the National Institute of Standards and Technology (NIST) started developing and evaluating analytical methods to provide forensic scientists with the tools necessary. This presentation will summarize sample homogenization, extraction, and clean-up procedures for the determination of Δ8-THC, Δ9-THC, tetrahydrocannabinolic acid (THCA), and total Δ9-THC in smokable hemp plant samples, hemp oils, and vape liquids. Additionally, commercial hemp samples that were supposed to be at or below the federal limit of 0.3% were analyzed by liquid chromatography photodiode array detector (LC-PDA); however, in the case of smokable hemp plant samples, approximately 93% were measured by NIST to have a total Δ9-THC value above this limit. Similar studies will be highlighted for other Cannabis matrices and comparisons will be provided between NIST mass fractions and the manufacturers’ fractions. Reference 1. United States Department of Agriculture. “Hemp Acreage and Production Survey.” Last modified December 5, 2022. https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Hemp/index.php.