Institut de Police Scientifique, School of Criminal Sciences, Batochime, University of Lausanne, 1015 Lausanne-Dorigny, Switzerland.
Forensic Sci Int. 2010 Jul 15;200(1-3):87-92. doi: 10.1016/j.forsciint.2010.03.034. Epub 2010 Apr 24.
Cannabis cultivation in order to produce drugs is forbidden in Switzerland. Thus, law enforcement authorities regularly ask forensic laboratories to determinate cannabis plant's chemotype from seized material in order to ascertain that the plantation is legal or not. As required by the EU official analysis protocol the THC rate of cannabis is measured from the flowers at maturity. When laboratories are confronted to seedlings, they have to lead the plant to maturity, meaning a time consuming and costly procedure. This study investigated the discrimination of fibre type from drug type Cannabis seedlings by analysing the compounds found in their leaves and using chemometrics tools. 11 legal varieties allowed by the Swiss Federal Office for Agriculture and 13 illegal ones were greenhouse grown and analysed using a gas chromatograph interfaced with a mass spectrometer. Compounds that show high discrimination capabilities in the seedlings have been identified and a support vector machines (SVMs) analysis was used to classify the cannabis samples. The overall set of samples shows a classification rate above 99% with false positive rates less than 2%. This model allows then discrimination between fibre and drug type Cannabis at an early stage of growth. Therefore it is not necessary to wait plants' maturity to quantify their amount of THC in order to determine their chemotype. This procedure could be used for the control of legal (fibre type) and illegal (drug type) Cannabis production.
瑞士禁止为生产毒品而种植大麻。因此，执法部门经常要求法医实验室从没收的材料中确定大麻植物的化学型，以确定种植是否合法。按照欧盟官方分析协议的要求，从成熟的花中测量大麻的 THC 含量。当实验室面对幼苗时，他们必须让植物成熟，这意味着这是一个耗时且昂贵的过程。本研究通过分析叶片中的化合物并使用化学计量学工具，研究了纤维型与毒品型大麻幼苗的区分。研究人员在温室中种植了瑞士联邦农业局允许的 11 种合法品种和 13 种非法品种，并使用气相色谱-质谱联用仪进行了分析。确定了在幼苗中具有高区分能力的化合物，并使用支持向量机 (SVM) 分析对大麻样本进行了分类。整套样本的分类率超过 99%，假阳性率低于 2%。该模型允许在早期生长阶段区分纤维型和毒品型大麻。因此，没有必要等到植物成熟后再定量其 THC 含量来确定其化学型。该程序可用于控制合法（纤维型）和非法（毒品型）大麻的生产。
