Desenvolvimento de um procedimento para a identificação de perfis químicos em amostras de cocaína por eletroforese capilar com detecção condutométrica sem contato (CE-C4D)

Abstract

This work presents a new analytical procedure for the determination of diluents, adulterants and reagent traces used in the cocaine extraction and refining process. The procedure proposed, employing capillary electrophoresis, allows the identification of nine chemical species (cocaine, levamisole, lidocaine, boric acid, Cl-, NO2-, NO3-, SO42- and CO32-) simultaneously in approximately 2.5 minutes. The determination of boric acid by capillary electrophoresis in cocaine samples has not been reported previously in the literature, as well as the simultaneous determination of cocaine, levamisole, lidocaine and inorganic anions. For the determination of the proposed species, a running electrolyte composed of 10 mmol L-1 TAPS was used; 0.2 mmol L-1 CTAB and pH 8.8, adjusted with NaOH. The procedure shows detection limits values between 1.0 x 10-3 mmol L-1 and 2.0 mmol L-1, and addition and recovery results between 72 and 130%. Calibration curves for all species showed correlation coefficients greater than 0.998 and relative standard deviation less than 7% (n = 12) for the peak area. The procedure was applied to 50 samples seized in Uberaba-MG from March 2018 to March 2019 and made it possible to identify three main profiles in the region through multivariate statistical treatments, and to suggest the main chemical profile of the drug that arrives in the city and the main method of dilution and tampering by local distributors. The procedure does not require complex sample preparation, with high analytical frequency and can be used as a tool to identify and quantify cocaine, adulterants and diluents in forensic posts and to contribute to investigations aimed at combating drug trafficking crime.