The differentiation of fibre- and drug type Cannabis seedlings by gas chromatography/mass spectrometry and chemometric tools

Institut de Police Scientifique, School of Criminal Sciences, Batochime, University of Lausanne, 1015 Lausanne-Dorigny, Switzerland.
Forensic science international (Impact Factor: 2.14). 04/2010; 200(1-3):87-92. DOI: 10.1016/j.forsciint.2010.03.034
Source: PubMed


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.

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    • "Detection was by Odyssey Ò Imaging system (Li-COR Biosciences, Lincoln, NE, USA). pCB 'mix' was a set ratio of 5.2 consisting of 1 lM THC/100 nM CBN/300nM CBD (Broseus et al. 2010). "
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    Inflammopharmacology 08/2014; 22(5). DOI:10.1007/s10787-014-0214-z
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    • "Hemp varieties used for drug consumption, characterized by a high content of D-9-tetrahydrocan- nabinol (THC), are often not distinguishable morphologically from fiber varieties with a lower content of THC. C. sativa subspecies are divided into several chemical phenotypes. The relative proportions of THC, CBN (cannabinol) and CBD have been used by various authors for distinguishing three predominant chemotypes: I (drug type, the predominant cannabinoid is THC) II (intermediate type, the predominant cannabinoids are THC and CBD) and III (fibre type, the predominant cannabinoid is CBD) (Broseus et al. 2010). The D-1-tetrahydrocannabinolic acid synthase is considered to be a key enzyme controlling the psychoactivity (i.e. level of THC) of Cannabis because this enzyme mediates the biosynthetic step of THC (Shoyama et al. 2012). "
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    ABSTRACT: Accessions of wild and domesticated hemp (Cannabis sativa L.) originating from Colombia, Mexico, California, Bolivia, Thailand, Afghanistan, Serbia, Hungary, south Africa and different regions of China, were studied by means of DNA polymorphisms in order to discriminate between drug and fiber types. Analysis of molecular variance (AMOVA) was used to partition the total genetic variance within and among populations. The significance of the variance components was tested by calculating their probabilities based on 999 random permutations. AMOVA revealed 74 % variation among accessions and 26 % within accessions, all AMOVA variation was highly significant (P < 0.001). The cluster analysis of molecular data, grouped accessions into eight clusters and gave a matrix correlation value of r = 0.943, indicating a very good fit between the similarity values implied by the phenogram and those of the original similarity matrix. In this study, DNA polymorphisms could discriminate the fiber and drug types, and accessions were grouped in accordance to their classification and uses. In addition, seed size variation and micromorphological characters of seeds were studied by means of a scanning electron microscope (SEM). Seeds varied significantly in size, and were bigger in the fiber types. SEM analysis exhibited variation of micromorphological characters of seeds that could be important for discriminating the fiber or drug types.
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