Extractive Photometric Simuitaneous Determination of Copper(Il) and Gold(Ill) with Syn-Phenyl-alpha-Pyridyl Ketoxime : Analysis of Gold-plating Bath

Inorganic Chemistry Laboratories, Shivaji University, Kolhapur-416004.

Manuscript received 10 May 1974 ; revised 6 February 1975; accepted 22 March 1975

A spectrophotometric method is developed for the simultaneous estimation of gold and copper in alloys or plating bath. Syn-phenyl-alpha-pyridyl ketoxime forms complexes with gold(III) and copper(II) at pH 9, which are extractable in chloroform. A method based on the measurements of absorbances at 455 and 550 urn is presented. The composition of an unknown mixture of these elements or the plating bath solution can be determined by solving the following simultaneous equations.

                                                          [Au] x 10⁴=4.164 x A₄₆₅-1,727 x A₅₅₀
                                                          [Cu] x 10⁴ = 4.657 x A₅₅₀-0.270 x A₄₅₅

The interference due to CN^-, pyridine, thiourea etc. in the determination of the composition of the plating bath can be eliminated by using formaldehyde. The standard deviation of the method is ± 0.71% for Au and ± 0.63% for Cu.