Catalytic spectrophotometric determination of trace copper with arsenazoIII-potassium periodate system

In the medium of phosphoric acid,the decoloring reaction of arsenazoⅢ oxidized by KIO_4 could be remarkably catalyzed by Cu?.Based on the experimental results,a new method for the determination of trace copper? by the catalytic kinetic spectrophotometry was estabalished and the kinetic conditions about the new reaction were investigated.The results showed that the catalytic reaction was a quasi-zero-order reaction.The apparent rate constant was 1.08×10~(-3)·s~(-1),and the activation energy of the reaction was 100.1 kJ·mol~(-1).The linear range of the determination was 1.2×10~(-7)-1.0×10~(-4) g·L~(-1) and detection limit was 9.5×10~(-8)g·L~(-1) for copper?.The method is simple,rapid,and sensitive.The method has been used to the determination trace copper in steel and water with satisfactory results.