Color-Fading Spectrophotometric Determination of Cerium with DBC-Arsenazo

摘要

In the medium of 0.18 approx 1.08 mol centre dot L~(-1) sulfuric acid , cerium(IV) has the color-fading effect on DBC-arsenazo. The apparent molar absorptivity of the color-fading reaction is epsilon 530 nm = 1.03 X 10~4 L centre dot mol~(-1) centre dot cm~(-1). Beer's law is obeyed over the range of 1.20 approx 12.0 mu g centre dot ml~(-1) of Ce (IV) which shows a linear relationship with the decrease in the absorbance of the colored solution. The effect of thirty-six coexisting ions was studied. The method was applied to the determination of the trace amount of cerium in water samples and has the advantage of high accuracy and good selectivity.