Laboratory of Analysis and Research in Toxicology, Department of Pharmacy, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Chemistry Institute, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Feb 15;173:318-323. doi: 10.1016/j.saa.2016.09.040. Epub 2016 Sep 22.
Cannabis sativa L. (cannabis, Cannabaceae), popularly called marijuana, is one of the oldest plants known to man and it is the illicit drug most used worldwide. It also has been the subject of increasing discussions from the scientific and political points of view due to its medicinal properties. In recent years in Brazil, the form of cannabis drug trafficking has been changing and the Brazilian Federal Police has exponentially increased the number of seizures of cannabis seeds sent by the mail. This new form of trafficking encouraged the study of cannabis seeds seized germinated in a greenhouse through NIR spectroscopy combined with chemometrics. The plants were cultivated in a homemade greenhouse under controlled conditions. In three different growth periods (5.5weeks, 7.5weeks and 10weeks), they were harvested, dried, ground and directly analyzed. The iPCA was used to select the best NIR spectral range (4000-4375cm) in order to develop unsupervised and supervised methods. The PCA and HCA showed a good separation between the three groups of cannabis samples at different growth stages. The PLS-DA and SVM-DA classified the samples with good results in terms of sensitivity and specificity. The sensitivity and specificity for SVM-DA classification were equal to unity. This separation may be due to the correlation of cannabinoids and volatile compounds concentration during the growth of the cannabis plant. Therefore, the growth stage of cannabis can be predicted by NIR spectroscopy and chemometric tools in the early stages of indoor cannabis cultivation.
大麻（大麻，大麻科），俗称大麻，是人类已知的最古老的植物之一，也是全球使用最广泛的非法药物。由于其药用特性，它也成为了科学界和政治界日益关注的话题。近年来，在巴西，大麻毒品的贩运形式发生了变化，巴西联邦警察对数以百万计的通过邮件发送的大麻种子的扣押数量呈指数级增长。这种新的贩运形式促使人们通过近红外光谱结合化学计量学研究在温室中发芽的大麻种子。这些植物在自制的温室中在受控条件下种植。在三个不同的生长阶段（5.5 周、7.5 周和 10 周），对其进行了收割、干燥、粉碎和直接分析。iPCA 用于选择最佳的近红外光谱范围（4000-4375cm），以开发无监督和监督方法。PCA 和 HCA 显示了不同生长阶段的三组大麻样品之间的良好分离。PLS-DA 和 SVM-DA 对样品的分类在灵敏度和特异性方面均取得了较好的效果。SVM-DA 分类的灵敏度和特异性等于 1。这种分离可能是由于大麻植物生长过程中大麻素和挥发性化合物浓度的相关性所致。因此，可以通过近红外光谱和化学计量学工具在室内大麻种植的早期阶段预测大麻的生长阶段。
