“Also, while the absorbance spectrum of DDC at 280 nm was decreased by 50% either by Co2+ , Cd2+ or by H2O2, a 90% reduction in absorbance occurred if DDC + H2O2 mixtures were treated either by Cu2+ or by Co2+, but not by Cd2+.”
“The cyclovoltammetry patterns of DDC were drastically changed either by Cu2+, Co2+ or by Cd2+ suggesting a strong interaction of the metals with DDC.”