Catalytic Photometric Determination of Trace Amounts of Mercury in Water

It was found that the reaction between potassium ferrocyanide and 1,10-phenanthroline was catalyzed by Hg(Ⅱ) ion in dil.HNO3 solution.Absorbance values of the catalyzed (A) and non-catalyzed (A0) reaction systems were taken at the wavelength 508 nm.Linear relationship between values of ΔA(A-A0) and concn.of Hg(Ⅱ) added to the reaction system was found in the range from 2.0×10-3 to 6.4×10-2mg·L-1 (r=0.987 6) with a molar absorptivity (ε508) of 5.92×105L·mol-1·cm-1.The proposed method was applied to the determination of mercury in a water sample and the value of RSD (n=6) calculated from the analytical results was 0.134%,values of recovery obtained in the recovery test were in the range of 97.5%-102.7%.