Studies on the Hydrolysis, Dissociation Constant and Limiting Molar Conductance of Dopamine Hydrochloride
Thimmasandra Narayan Ramesh *
Department of Chemistry, University College of Science, Tumkur University, Tumkur, 572 103, India.
*Author to whom correspondence should be addressed.
Abstract
Dopamine hydrochloride (C₈H₁₁NO₂•HCl) is a stable, water-soluble salt form of dopamine, crucial for regulating motor control, reward mechanisms, and cognitive functions. In this study, a 0.1 M solution of dopamine hydrochloride was prepared, and its pH was measured, followed by dilutions to 0.05 M and 0.025 M. The hydrolysis constant (Kₕ) and dissociation constant (Kb) were calculated as the mean ± standard deviation from two independent experiments, yielding values of 3.5677 × 10⁻⁶ and 2.833 × 10⁻⁹, respectively. Also conductance measurements were carried out for the dopamine hydrochloride solution at different concentrations. Using the conductance values, the limiting molar conductance of dopamine hydrochloride was obtained (Lmo = 15.11 Scm2mol-1). These results provide insights into the physical parameters which are crucial towards understanding the chemical behaviour of dopamine hydrochloride in aqueous solutions.
Keywords: Hydrolysis, hydrolysis constant, conductance, limiting molar conductance, dopamine hydrochloride