Determination of catecholamines in urine by liquid chromatography and electrochemical detection after online sample purification on immobilized boronic acid

Abstract Norepinephrine, epinephrine and dopamine in urine were measured by an automated liquid chromatographic method. After sample purification on a column containing silica-immobilized boronic acid, which showed great affinity for catecholamines at neutral pH, the catecholamines were eluted by backflushing with an acidic mobile phase and transferred to a cation exchange for separation. Detection was performed electrochemically and the relative standard deviation was 2% for the analysis of endogenous concentrations in human urine.