Interfaces between two immiscible electrolyte solutions are recognized as a simplified model for biological systems and they can be of great relevance to the characterization of biomolecules and their role in biological systems. In this work, ion transfer and facilitated ion transfer of protonated catecholamines (dopamine and noradrenaline) by dibenzo-18-crown-6 are investigated at the water/1,6-dichlorohexane interface. The formation constant of the complex between both dopamine and noradrenaline with dibenzo-18-crown-6 was evaluated and the experimental conditions for the analytical determination of those catecholamines are established. These results can improve the understanding of the pharmacodynamics of the catecholamines, and contribute to the study of their interaction with biological membranes. Furthermore it can be used to develop an alternative method for the determination of neural signal transmission catecholamines.