Study on determination of trace Copper(II) by catalytic kinetic discoloring spectrophotometry and its application in food

A catalytic kinetic spectrophotometric method for the determination of trace Cu(Ⅱ) was developed in this paper.This method is based on the discoloring oxidation between methylene blue and hydrogen peroxide catalyzed by Copper(Ⅱ) in the medium of HCl solution.The influential factors of reaction and the optimum conditions for the determination of Cu(Ⅱ) were investigated in detail.The linear determination range is between 0~30 ×10~(-9) g·mL~(-1) of Copper(Ⅱ).A detection limit of 1.92×10~(-9) g·mL~(1) is achieved.The RSD are 1.16 % and the recoveries are 98.5%～103.7%.The method can be applied to the determination of copper in foodstuffs with satisfactory results.