Comportamento de partição de cocaína e de seus adulterantes em SABs: proposta de um novo método para a identificação da droga

• Ano de defesa: 2012
• Autor(a) principal: Ferreira, Gabriel Max Dias
• Orientador(a): Silva, Luis Henrique Mendes da
• Banca de defesa: Andrade, Nélio José de , Carvalho, Raquel Moreira Maduro de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Agroquímica
• Departamento: Agroquímica analítica; Agroquímica inorgânica e Físico-química; Agroquímica orgânica
• País: BR
• Palavras-chave em Português: Cocaína; Adulterantes; Sistemas aquosos bifásicos; Partição
• Palavras-chave em Inglês: Cocaine; Adulterants; Aqueous two phase systems; Partition
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA
• Link de acesso: http://locus.ufv.br/handle/123456789/2119

In this work, we evaluated the partition behavior of cocaine and its adulterants in aqueous two phase systems (ATPS). The finality of this studied was introducing ATPS as an efficient and selective alternative to identification of these solutes in apprehended sample by police. Benzocaine (BEN), fenacetine (PHE), procaine (PRO), caffeine (CAF) and lidocaine (LID) adulterants besides cocaine, in hydrochloride (CoH) and freebase (CoF) forms, were studied. ATPS formed by Poly(oxide ethylene) (PEO 1500) + Li2SO4 + H2O at different pH values and L35 copolymer + salt (Li2SO4 or Na2SO4) + H2O were utilized. The partition coefficients (KS) of all solutes in all ATPS evaluated were higher than 1 and always increased with the increase in the tie line length (TLL). KS values in ATPS formed by PEO 1500 + Li2SO4 + H2O at pH 6.0 increased in following order: KLID < KPRO < KCAF < KCoF < KCoH < KPHE < KBEN. Polymer hydrophobicity, electrolyte nature and pH of ATPS influenced directly in this order. The ratio between two KS values for two distinct ATPS was determinate for each solute. This ratio was a strategic and fundamental parameter that allowed the distinction between both forms of cocaine and also between these and its adulterants. The ratio K12/K6, where K6 and K12 are the KS values in PEO 1500 + Li2SO4 + H2O ATPS at pH 6.0 and 12.0, respectively, allowed distinguishing the CoH among all solutes evaluated. The effect of polymer hydrophobicity on the partition coefficients was fundamental to differentiate the CoF of the other species. In view of results obtained in this work a new field of studied arises in forensic chemistry: application of ATPS in analysis of cocaine identification.