Diffusion of levodopa in aqueous solutions of hydrochloric acid at 25 °C

• Autor(a) principal: Barros, Marisa C. F.
• Data de Publicação: 2014
• Outros Autores: Ribeiro, Ana C. F., Esteso, Miguel A., Lobo, Victor M. M., Leaist, Derek G.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/27115; https://doi.org/10.1016/j.jct.2013.12.010
• topic: Levodopa; Diffusion coefficient; Transport properties; Aqueous solutions

Ternary mutual diffusion coefficients (D11, D22, D12 and D21) measured by the Taylor dispersion method are reported for aqueous solutions of {levodopa (l-dopa) + HCl} solutions at 25 °C and HCl concentrations up to 0.100 mol · dm−3. The coupled diffusion of l-dopa (1) and HCl (2) is significant, as indicated by large negative cross-diffusion coefficients. D21, for example, reaches values that are larger than D11, the main coefficient of l-dopa. Combined Fick and Nernst–Planck equations are used to analyze the proton coupled diffusion of l-dopa and HCl in terms of the binding of H+ ions to l-dopa and ion migration in the electric field generated by l-dopa and HCl concentration gradients.