AMINES FOR DETECTION OF DOPAMINE BY GENERATION OF HYDROGEN-PEROXIDE AND PEROXYOXALATE CHEMILUMINESCENCE

A range of nitrogen-containing compounds (alkyl amines, piperazines, c yclohexylamines and nitrogen heterocyclics) were investigated for gene ration of hydrogen peroxide from dopamine and detection by peroxyoxala te chemiluminescence. Imidazole, ethyleneurea and allantoin among the nitrogen heterocyclic compounds tested generated hydrogen peroxide fro m dopamine following incubation at 60 degrees C, pH 9.5-10.5, for 0-30 min. Imidazole was the most effective for generation of hydrogen pero xide, but imidazole derivatives with a primary amine side chain (hista mine) or thiol (ethylenethiourea) were not effective. The presence of a ketone group (ethyleneurea, allantoin) did not hinder the reaction. Under optimal conditions (30 min incubation, 50 mmol/L imidazole) 10.5 nmol of dopamine could be detected. The cyclohexylamines tested produ ced low amounts of hydrogen peroxide (0.09-2.74% of light intensity wi th imidazole), and the piperazines and the alkyl amines tested produce d no detectable hydrogen peroxide. Imidazole reacts with the phenolic groups of dopamine in a different manner from monoamine oxidase, and a reagent containing imidazole, ethyleneurea or allantoin was useful fo r non-enzymatic detection of dopamine by peroxyoxalate chemiluminescen ce. (C) 1996 by John Wiley & Sons, Ltd.