Routine determination of urinary free catecholamines by high-performance liquid chromatography with electrochemical detection.

A simple and reliable high-performance liquid chromatographic method is described for the routine determination of the free catecholamines (norepinephrine, epinephrine and dopamine) in urine. The catecholamines are isolated from urine samples using small affinity chromatography columns prepacked with immobilised m-aminophenylboronic acid, separated by ion-pair reversed-phase liquid chromatography and quantified by electrochemical detection. Total analysis, including sample preparation time, is achieved in less than 30 min with analytical recoveries of 92-96% for all three catecholamines. Long-term stability and reproducibility of the liquid chromatographic system is attained by selection of optimised conditions for chromatographic separation with a formate mobile phase and produces detection limits of 1.4, 1.8 and 2.2 nmol/l for norepinephrine, epinephrine and dopamine, respectively, in urine samples and day-to-day coefficients of variation of less than 6%. Furthermore, the affinity isolation gels can be reused a minimum of ten times providing a rapid and cost-effective means of sample preparation.