SIMULTANEOUS DETERMINATION OF CATECHOLAMINE-RELATED COMPOUNDS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH POSTCOLUMN CHEMICAL OXIDATION FOLLOWED BY A FLUORESCENCE REACTION

A simple separation method involving isocratic elution and a selective postcolumn derivatization method involving chemical oxidation followed by a fluorescence reaction are described regarding a simultaneous high performance liquid chromatographic determination of catecholamines (three species) and their precursor (one species) and metabolites (nine species, all in the free form). These compounds, isoproterenol and 3,4-dihydroxyphenylpropanoic acid, are separated by ion-pair reversed-phase chromatography using a mixture of citrate buffer (pH 2.5) containing sodium octanesulfonate and methanol; they are then oxidized with periodate to the corresponding omicron-quinones, which are converted into fluorescent derivatives by reactions with meso-1,2-diphenylethylenediamine. The detection limits (S/N = 3, on column) vary from 15 to 570 fmol, depending on the compounds.