Development and Validation of a Gas Chromatographic Method for the Quantification of Minor Alkaloids in Cocaine

• Autor(a) principal: Maldaner,Adriano O.
• Data de Publicação: 2021
• Outros Autores: Zacca,Jorge J., Botelho,Élvio D., Silva,Dina R., Oliveira,Fillipe H.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532021000400823
• topic: validation; gas chromatography; cocaine; chemical profiling; minor alkaloids

The quantification of minor alkaloids in seized cocaine can provide information for drug profiling and law enforcement initiatives. This work presents the development and validation of an analytical method to quantitate minor alkaloids in cocaine samples using gas chromatography with flame ionization detector, after derivatization. The method was validated in accordance with the ISO/IEC 17.025:2017 requirements. The calibration was linear (determination coefficient (R2) ≥ 0.998), ranging from 1.0 to 3,500 mg L-1 for all target analytes with suitable selectivity and precision (relative standard deviation lower than 10%). The method showed stability and robustness with respect to analytical parameter variations and presented good accuracy (recovery ranging from 90 to 108%). The method was considered adequate to routine forensic analysis in simultaneous quantification of anhydroecgonine methyl ester, anhydroecgonine, methylecgonine, tropacocaine, norcocaine, N-formylcocaine, trimethoxycocaine, ecgonine, benzoylecgonine, trans- and cis-cinnamoylcocaine. Eleven cocaine samples seized in different Brazilian regions were analyzed and their relative amounts of tropacocaine and trimethoxycocaine with respect to cocaine indicate both the possible varieties of coca leaf used for cocaine production and the likely origin of drug samples (Bolivia/Peru or Colombia). The contents of other minor alkaloids depict aspects of sample history such as purification by oxidation, hydrolysis and dehydration by thermal processes.