Electrocatalytic oxidation and voltammetric determination of hydrazine in industrial boiler feed water using a cobalt phthalocyanine-modified electrode

摘要

A carbon paste electrode modified with cobalt phthalocyanine (CPECoPc) was developed and applied to the determination of hydrazine [N2H4] in industrial boiler feed water. The CPECoPc exhibited good electrocatalytical activity for hydrazine oxidation at pH 13. A linear correlation was obtained between anodic peak current (I-ap) and hydrazine concentration in the range of 1.25 x 10(-4) to 9.80 x 10(-4) mol L-1, fit by the equation Iap 1.47 + 4.90 x 10(5) [N2H4] with a correlation coefficient of 0.9967. A detection limit of 7.35 x 10(-5) mol L-1 was obtained. Recovery of hydrazine from three samples ranged between 99.0% and 102.9%. The modified electrode showed no interference by cations commonly present in boiler water, such as K+, Na+, Ca2+, Mg2+, Al3+, Pb2+, and Zn2+. The results obtained for hydrazine in boiler water using the proposed modified electrode are in agreement with the data obtained by a standard spectrophotometric method, at the 95% confidence level.