Plasma catecholamines including epinephrine (E), norepinephrine (NE), and dopamine (DA) are used to evaluate adreno-sympathetic 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. The reliable and simultaneous analysis of a broad panel of catecholamines is a powerful tool for the investigation of the hormone status, which is relevant for a variety of clinical questions and diagnoses.