National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Forensic Toxicol. 2022 Jan;40(1):125-131. doi: 10.1007/s11419-021-00592-9. Epub 2021 Jul 26.
Various forms of cannabidiol (CBD)-containing products are sold in Japan. CBD is easily converted to mixtures of ∆-tetrahydrocannabinol (∆-THC) and its isomer, ∆-THC, using household chemicals like diluted hydrochloric acid. This ease of production increases concerns regarding production of homemade THC mixtures. It is difficult to separate ∆-THC, ∆-THC, and CBD using thin-layer chromatography (TLC) on conventional silica gel. The selectivity of TLC on silver nitrate-impregnated silica gel (AgNO-silica gel) differs from that of conventional silica gel. This study thus aimed to evaluate the separation ability of AgNO-silica gel TLC.
To evaluate potential separation ability, standards of five THC isomers (∆-THC, ∆-THC, a pair of diastereomers of ∆-THC, and ∆-THC), CBD, CBN, and ∆-THCA were analyzed by 10% AgNO-silica gel TLC (developed using toluene, system A) and silica gel TLC [developed using n-hexane/diethyl ether (8:2, v/v), system B]. Then, mock homemade THC mixtures, prepared by heating crystalline CBD in acidic ethanol, were analyzed using systems A and B.
System A showed clear separation between the five THC isomers and between ∆-THC, ∆-THC, CBD, and their by-products in the mock homemade THC mixture. However, system B did not separate some combinations of THC isomers and gave a single group-like spot to the THC mixture.
AgNO-silica gel TLC shows high separation ability between THC isomers and among ∆-THC, ∆-THC, and CBD. It will thus be useful for analyzing homemade THC mixtures.
在日本，各种形式的含大麻二酚（CBD）产品均有销售。使用家用化学品（如稀盐酸），CBD 很容易转化为 ∆-四氢大麻酚（∆-THC）及其异构体 ∆-THC 的混合物。这种易于生产的特性增加了对自制 THC 混合物生产的关注。使用常规硅胶的薄层色谱法（TLC）很难分离 ∆-THC、∆-THC 和 CBD。硝酸银浸渍硅胶（AgNO-silica gel）上 TLC 的选择性与常规硅胶不同。因此，本研究旨在评估 AgNO-silica gel TLC 的分离能力。
为了评估潜在的分离能力，使用 10% AgNO-silica gel TLC（使用甲苯，体系 A）和硅胶 TLC [使用正己烷/二乙醚（8:2，v/v），体系 B]分析了 5 种 THC 异构体（∆-THC、∆-THC、一对 ∆-THC 的非对映异构体和 ∆-THC）、CBD、CBN 和 ∆-THCA 的标准品。然后，使用体系 A 和 B 分析了在酸性乙醇中加热结晶 CBD 制备的模拟自制 THC 混合物。
体系 A 清晰地区分了 5 种 THC 异构体以及模拟自制 THC 混合物中 ∆-THC、∆-THC、CBD 和它们的副产物。然而，体系 B 没有分离出某些 THC 异构体组合，并且对 THC 混合物给出了单个类似组的斑点。
AgNO-silica gel TLC 显示出 THC 异构体之间以及 ∆-THC、∆-THC 和 CBD 之间的高分离能力。因此，它将有助于分析自制 THC 混合物。
