Spectrophotometric Determination of Trace Amounts of Gold with 3-Methoxy-azomethine H as Colour Reagent in Microemulsion Medium

It was found that in an acetate buffer medium of pH 4.5,and in the microemulsion prepared by mixing CTMAB,n-butanol,n-heptane and water,a yellow coordination complex was formed among Au(Ⅲ),3-methoxy-azomethine H (MOAM H) and CTAMB with the mole ratio of 1∶1∶3. Absorption maximum of the complex was found at the wavelength of 450 nm. Apparent molar absorptivity obtained was (ε450) 2.6×105L·mol-1·cm-1. Beer′s law was kept in the range within 0.55 mg·L-1. In applying the method to determined trace amounts of gold in samples of gold ore,contents of gold found were in conformity with the results obtained by AAS. Recovery and precision of the method were tested,giving value of average recovery of 80% and value of average RSD′s (n=6) of 0.25%.