Plasma catecholamines including epinephrine (E), norepinephrine (NE), and dopamine (DA) are used to evaluate adrenosympathetic function in patients. Quantification of plasma catecholamine concentrations is clinically important for the diagnosis of pheochromocytoma and paraganglioma during dynamic clonidine tests. The low circulating concentrations of catecholamines and analytical interferences require tedious sample preparation and long chromatographic runs to ensure their accurate quantification by HPLC with electrochemical detection.