Determinação de cocaína e seus adulterantes empregando Cromatografia Gasosa acoplada à Espectrometria de Massas (GC-MS)

Abstract

Drug trafficking has been a major contributor to the increase in violence and is directly related to serious crimes such as homicides and robberies. In this scenario, cocaine stands out as one of the most consumed illicit drugs in Brazil, and is commonly mixed with adulterants and thinners that aim to increase the volume of the drug, thus increasing the profits of trafficking. The use of these adulterants and thinners makes the composition of commercialized cocaine unpredictable, generating and potentiating the health risks of users. Due to the importance of this theme, this work presents the identification of the main adulterants, diluents and alkaloids present in cocaine seizures, using gas chromatography coupled with mass spectrometry. The methodology applied to 78 samples seized in Uberaba-MG between March 2018 and March 2019, identified the presence of cocaine in 96% of the samples, and boric acid in 78%, in addition to caffeine (32.1%), phenacetin (30.8%), levamisole (21.8%), lidocaine (17.9%), aminopyrine (2.6%), and for the first time reported, phendimetrazine in 6.4%. It was also possible to identify alkaloids co-extracted from coca leaves along with cocaine during the process of extracting and refining the drug, they were: methylecgonidine ester, cis-cinnamoylocaine, trans-cinnamoylocaine, tropococaine and Benzoilecgonine. The applied methodology combined with the treatment of multivariate data revealed the three main combinations of substances used for the dilution and adulteration of the drug. Based on previous work, the analysis of alkaloids made it possible to suggest the geographical origin of the samples according to the ratio between the areas of the alkaloid peaks and the area of the cocaine peak, and identified that possibly 36% of the seized samples are from Colombia, 18 % of Peru, 15% of Bolivia, 4% of Ecuador and 27% was not possible to suggest. The methodology also edited to identify the degree of oxidation of, based on the ratio between cis and trans cinnamoylocaine and cocaine, and showed that 69% of those presented have a low degree of oxidation, that is, they have relevant concentrations of alkaloids in addition to cocaine, 28% it has a high oxidation degree and 3% medium oxidation degree. The identification of chemical profiles proved to be effective in combating the crime of drug trafficking by identifying a correlation between the routes and people responsible for distributing the drug in Uberaba-MG.