Separation of urinary catecholamines and catecholamine metabolites by high-pressure liquid chromatography.

A series of high-pressure liquid chromatographic (hplc) procedures are described for the separation of all major and most minor catecholamine metabolites present in human urine. The amines and metabolites are first concentrated and partially purified by traditional methods, ion-exchange and alumina chromatography. Final separations are then performed with hplc. Our system is specifically designed to study dopamine Phydroxylation in vivo. [3H]Dopamine is administered intravenously to human subjects, and then all the excreted [3H]dopamine metabolites and 13H]norepinephrine metabolites are separated and assayed. The high degree of resolution achieved with hplc makes it possible to separate the small population of [3H]norepinephrine metabolites from the much larger population of [3H]dopamine metabolites. The ratio of total excreted [3H]norepinephrine metabolitesltotal excreted [3H]dopamine metabolites averages 0.029 2 0.005 in urine samples collected during the hrst 6 h following the administration of isotope.