An automated trihydroxyindole procedure for the differential analysis of catecholamines.

An automated trihydroxyindoleprocedure for the differential estimation of epinephrine and norepinephrinein tissues,urine, and blood is presented in detail. After an initial purification of the catecholaminesby adsorption on aluminum oxide, the neutralized eluates are subjected to automatic analysis, in which potassiumferricyanide 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 samplesthrough the system, first with ascorbicacid stabilization to obtain the combined fluorescenceof both amines and then with thioglycolic acid stabilization to obtain the fluorescence of norepinephrinealone.