ELECTROCATALYTIC AMPEROMETRIC DETECTION OF HYDROXYLAMINE WITH A PALLADIUM-MODIFIED CARBON-PASTE ELECTRODE

Carbon paste electrodes (CPEs), modified by addition of Pd powder to t he paste and electroactivation, exhibited electrocatalytic activity to wards hydroxylamine. Electrogenerated palladium(0) at the electrode su rface was found to be involved in the electrocatalytic oxidation of NH 2OH. The electrode was employed as an amperometric detector for flow i njection systems. Repeated injections (60) of hydroxylamine (5 ng) sho wed a relative standard deviation of 4.0%. Linear relation between the current and the analyte concentration was found between 0.1 and 10 ng of hydroxylamine. The detection limit was 20 pg NH2OH (3 sigma). The applicability of the method to the determination of hydroxylamine in r iver water was investigated.