Micelle-Sensitized Catalytic Spectrophotometric Determination of Trace Amount of Copper(Ⅱ) in Water

In a HCl solution of pH 3.1 and in the presence of CTMAB,the color-fading of methyl orange by oxidation with hydrogen peroxide was catalyzed by cupric ion,and the sensitivity of the color-fading reaction was found to be 2-3 times higher than that of the reaction in the absence of CTMAB.Based on these facts,a micelle-sensitized catalytic spectrophotometric method for determination of trace amount of copper(Ⅱ) was proposed.Linear relationship between the magnitude of decrease in absorbance ΔA(A0-A) and mass concentration of copper(Ⅱ) was obtained in the range of 1.0×10-3-4.0×10-2mg·L-1.Detection limit (3S/N) found was 4.6×10-4mg·L-1.In the determination of traces of copper(Ⅱ) in river water sample by the proposed method,values of recovery found by standard addition method were in the range from 98.4% to 103.0%,with values of RSD′s (n=6) less than 3%.