An Automated Trihydroxyindole Procedure for the Differential Analysis of Catecholamines

Abstract

Abstract An automated trihydroxyindole procedure for the differential estimation of epinephrine and norepinephrine in tissues, urine, and blood is presented in detail. After an initial purification of the catecholamines by adsorption on aluminum oxide, the neutralized eluates are subjected to automatic analysis, in which potassium ferricyanide and an alkaline stabilizing agent are automatically mixed sequentially with the dialyzed catecholamines. The fluorescent trihydroxyindole derivatives formed are then delivered to a flow cell in a fluorometer and the fluorescence recorded. A differential estimation is obtained by running samples through the system, first with ascorbic acid stabilization to obtain the combined fluorescence of both amines and then with thioglycolic acid stabilization to obtain the fluorescence of norepinephrine alone.