Marijuana and hemp are different cultivars of the species, Cannabis sativa. Trichomes within these genetically distinct forms result in different chemical constituents within the plant matrix. While drug-type cannabis yields higher total Δ9-THC concentrations, industrial or consumer-based hemp products are typically rich in cannabidiol or CBD-rich. Regulatory changes following the passage of agricultural legislation in the United States defines hemp as C. sativa containing no more than 0.3 % Δ9-THC on a dry weight basis. This threshold, which effectively differentiates legal hemp from illegal marijuana, presents a challenge to operational forensic laboratories. In this report we describe a decision-point assay to differentiate hemp from marijuana using a 1 % threshold. Methanolic extracts of C. sativa were analyzed using gas chromatography-mass spectrometry (GC–MS) using a deuterated analog (Δ9-THC-D3). Synchronous selected ion monitoring (SIM) and full scan acquisition was used for targeted analysis of Δ9-THC at the decision-point. Assay performance was evaluated in terms of limit of detection, linearity, carryover, selectivity, precision, accuracy and extract stability. Two analytical approaches are presented. Extraction efficiencies of Δ9-THC from plant matrix were 80–92 %, and decarboxylation of Δ9-tetrahydrocannabinolic acid (THCA) was 67 %. Interferences arising from the cyclization of CBD to produce Δ9-THC in the GC inlet were addressed using concentrations in excess of those typically encountered in plant samples. Accuracy was established across the specified range of the assay using known reference materials containing 0.12 to 10.1 % Δ9-THC. No false positive or negative results were identified (n = 140) using both analytical approaches.

大麻和大麻是大麻品种的不同品种。这些遗传上不同形式的毛状体导致植物基质内产生不同的化学成分。虽然药物型大麻产生较高的 Δ9-THC 总浓度，但工业或消费类大麻产品通常富含大麻二酚或 CBD。美国农业立法通过后的监管变化将大麻定义为以干重计含有不超过 0.3% Δ9-THC 的苜蓿。这一阈值有效区分了合法大麻和非法大麻，对法医实验室的运作提出了挑战。在本报告中，我们描述了使用 1% 阈值区分大麻和大麻的决策点测定。使用氘代类似物 (Δ9-THC-D3) 通过气相色谱-质谱 (GC-MS) 分析苜蓿的甲醇提取物。同步选择离子监测 (SIM) 和全扫描采集用于在决策点对 Δ9-THC 进行有针对性的分析。从检测限、线性、残留、选择性、精密度、准确度和提取物稳定性方面评估测定性能。提出了两种分析方法。从植物基质中提取 Δ9-THC 的效率为 80-92%，Δ9-四氢大麻酸 (THCA) 的脱羧率为 67%。使用超过植物样品中通常遇到的浓度来解决 GC 入口中 CBD 环化产生 Δ9-THC 所产生的干扰。使用含有 0.12 至 10.1 % Δ9-THC 的已知参考材料在指定的测定范围内确定准确度。使用两种分析方法均未发现假阳性或阴性结果 (n = 140)。