Voltammetric determination of nitric oxide on cobalt phthalocyanine modified microelectrodes

The catalytic activity of a carbon fiber microelectrode modified with cobal t phthalocyanine (CoPc-ME) for the detection of nitric oxide in the presenc e of possible interfering molecules (dopamine and serotonin) is examined. A linear plot is observed for the variation of the catalytic currents with N O concentration in the presence of excess dopamine and serotonin, showing t hat NO may be determined in the presence of these molecules. However, oxida tion currents due to serotonin were found to decrease with increase in NO c oncentration. The CoPc-ME could also detect NO added to blood or its compon ents, the oxidation currents for NO, however, decreased rapidly with time. The decrease in currents was slower in blood serum, followed by whole blood , with a faster decrease being observed in blood plasma. (C) 2001 Elsevier Science BN. All rights reserved.