Gas-phase fragmentation reactions of protonated cocaine: New details to an old story

Autor(es)

Dias, Herbert J. ^{[1, 2]} ; Bento, Mariana V. B. ^[2] ; da Silva, Eder H. ; Saturnino-Junior, Andrade ^[2] ; de Oliveira, Marcelo F. ^[1] ; Vessecchi, Ricardo ^[1] ; Parreira, Renato L. T. ^[2] ; Crotti, Antonio E. M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ribeirao Preto, SP - Brazil

^[2] Univ Franca, Nucleo Pesquisas Ciencias Exatas & Tecnol, Franca, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Mass Spectrometry; v. 53, n. 3, p. 203-213, MAR 2018.
• Citações Web of Science: 4

Resumo

We have used a combination of multiple stage mass spectrometry (MSn) experiments, hydrogen/deuterium exchange experiments, and thermochemical data estimated by computational chemistry calculations at the B3LYP/6-31+G(d,p) level of theory to revisit the gas-phase fragmentation of protonated cocaine. The lone pair of nitrogen participates in major fragmentation routes of protonated cocaine, to generate cyclic iminium ions. The structure of product ion m/z 182, which has been previously proposed in the literature, was shown to be unstable; therefore, we have decided to revisit it. Here, we propose another ion structures for the product ion m/z 182 that is supported by thermochemical data. Compared with the formation of other product ions, the formation of the most intense product ions in the collision-induced dissociation spectrum of protonated cocaine (m/z 182 and m/z 82) is the most energetically favorable. We propose the structure and formation of m/z 122 and m/z 91 for the first time. We suggest that m/z 91 originates from m/z 122 instead of m/z 119, as fully supported by MSn experiments. The results of this study could help to study and quantify cocaine metabolites. (AU)

• Processo FAPESP: 13/20094-0 - Avaliação da atividade antiparasitária e inseticida de compostos benzofurânicos e estudo de suas reações de fragmentação em fase gasosa empregando espectrometria de massas sequencial
• Beneficiário: Antônio Eduardo Miller Crotti
• Modalidade de apoio: Auxílio à Pesquisa - Regular