On-line monitoring of trace amounts of copper(II) in steam condensate and boiler feed-water by flow injection analysis based on its catalytic effect on the oxidation of hydroquinone by hydrogen peroxide

A flow injection analysis (FIA) method for on-line monitoring of trace amounts of copper(II) in steam condensate and boiler feed-water is described. This method is based on the catalytic effect of copper(II) on the oxidation of hydroquinone by hydrogen peroxide, the quinone produced being detected using UV-absorption at 490 nm. The effects of pH, temperature, the concentrations of hydroquinone and hydrogen peroxide, and reaction time on the determination of the selectivity and the sensitivity of this method were investigated. An FIA-kinetic determination method with both high selectivity and sensitivity was obtained by the optimization of the detection conditions. Trace amounts of copper(II) in steam condensate and boiler feed-water in power stations were successfully analyzed on-line using this method.