Estudo do perfil químico de apreensões de maconha por RMN de 1H e outras técnicas analíticas
Nenhuma Miniatura disponível
Data
2017-03-30
Autores
Leite, Júlia de Almeida
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal do Espírito Santo
Resumo
Marijuana is the most consumed illicit drug in the world. It’s derived fromCannabis sativa L. plant. In this work, a total of 156 marijuana samples seized in the state of Espírito Santo (ES) –Brazil were studied and analyzed by 1H NMR in order to identify their major cannabinoids. Firstly, for the optimization of the identification by NMR, extraction tests were realized with different solvents and the method with the combination methanol + maceration + deuterated chloroform for NMR analyses was chose. By this technique it was observed a big similarity between the samples from the obtained spectra. After 1H NMR analyses, a crude extract of all samples was submitted to HPLC with the purpose to purify these compounds to serve as reference substances. Nine fractions were obtained and then analyzed by NMR and GC-MS, and five presented cannabinoids confirmed by the latter technique. ?9-THC (?9-tetrahydrocannabinol), ?9-THCA (?9-tetrahydrocannabinolic acid), ?8-THC (?8-tetrahydrocannabinol),11-hydroxycannabinol, CBV (cannabivarin) and CBN (cannabinol) were found and their chemical structures were confirmed by GC-MS. The latter compound was obtained with high purity (˜100%), being able to serve as reference material, while the others were obtained as less complex mixtures. Other cannabinoids as canabichromene, canabicyclol and cannabicoumaronone were also found in the crude marijuana extract. The 156 samples were also analyzed by MS and it was noticed between them the same similarity observed by NMR. The chemometric technique Principal Component Analysis (PCA) was applied to the NMR and MS obtained data and the same result was verified for both techniques: naturally grouped samples indicating that they are similar. This fact may suggest the possibilitythatall the marijuana seized in ES can come from a same source, entering the state through a same location and then being distributed to the cities. For a new PCA applied to NMR data, with variables selection for the spectra, it was observed thatthe samples were grouped through the months, differentiating into two groups (July/2014 to January/2015 and February/2015 to July/2015), what may indicate the existence of new and old samples. In addition, using three fractions obtained after HPLC purification of the crude marijuana extract, for the application of a supervisioned PCA, it was possible to confirm again how similar the seized samples are, and also to observe that their chemical profile presenteda greater similarity with the 1H NMR spectrum of the isolated fraction containing the mixture of ?8-THC + ?9-THC + CBN
Descrição
Palavras-chave
Marijuana , 1H NMR , GC-MS , HPLC , MS , PCA , Maconha
Citação
LEITE, Júlia de Almeida. Estudo do perfil químico de apreensões de maconha por RMN de 1H e outras técnicas analíticas. 2017. Dissertação (Mestrado em Química) – Universidade Federal do Espírito Santo, Vitória, 2017.