ELECTROCATALYTIC BEHAVIOR OF SEVERAL COBALT COMPLEXES - DETERMINATIONOF HYDRAZINE AT NEUTRAL PH

Four cobalt complexes (cobalt(II) acetylacetonate and 8-hydroxyquinoli nate and cobalt(III) 8-hydroxyquinolinate and diethyldithiocarbamate) were tested as mediators to modify carbon paste electrodes with a view to obtaining a catalytic effect for the hydrazine. Cobalt(II) acetyla cetonate was found to exert no catalytic effect as the likely result o f ligand having to stabilize higher oxidation states of Co potentially involved in the catalytic process. The effects of the electrolyte and pH were examined and found to be important. The proposed chronoampero metric determination for hydrazine features limits of detection at the 99% confidence level of 1.6 mM with cobalt(III) diethyldithiocarbamat e, 1.5 mM with cobalt(III) 8-hydroxyquinolinate and 2.0 mM with Co(II) 8-hydroxyquinolinate. The RSD for 2 mM hydrazine was always less than 8%.