Spectrophotometric Determination of Micro-amounts of Gold in Gold Ores with Chlorophenolazo Rhodanine as Color Reagent

In an acetate buffer medium of pH 3.80 and in the presence of CTMAB,a stable red ternary complex was formed among Au(Ⅲ),chlorophenolazo rhodanine and CTMAB in the mole ratio of 1 to 3 to 1 respectively.Absorption maximum was found at the wavelength of 490 nm,where the apperent molar absorptivity was found to be 3.2×105L·mol-1·cm-1.Linear relationship between values of absorbance and concentration of Au(Ⅲ) was obtained in the range within 700 μg·L-1,in accordance to the linear regression equation of A=0.162 4 C+ 0.029 21 (r=0.999 8).The proposed method was used to determine microamounts of Au(Ⅲ) in 2 samples of gold ore,giving average values of recovery 98.0%.