title: Determination of copper in white-metal bearing alloys.
abstract: A method is proposed for the determination of copper in white-metal bearing alloys by direct controlled-potential electrolysis with a tantalum cathode at -0.32 V vs. SCE in a sulphate/bisulphate buffered electrolyte (pH 2) with fluoroboric acid and sodium tartrate as masking agents. Only Bi(III) interferes. Any co-deposited Bi can be corrected for by its spectrophotometric determination with Semi-Xylenol Orange after preconcentration with La(III) as carrier, from an ammoniacal solution containing the redissolved deposit. Any residual Cu(II) in the electrolyte is determined by spectrophotometry with 2,9-dimethyl-1, 10-phenanthroline. The standard deviation of this method has been found to be 0.03 mg (n = 12) and its relative standard deviation from 0.03 to 0.17%. It has been successfully used for referee analysis and certification of standard reference materials.
authors.affiliation: Shanghai Research Institute of Materials, Shanghai, MMEI, People's Republic of China.
authors.forename: N
authors.initials: N
authors.lastname: Zhou
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Ju
authors.forename: R Q
authors.initials: RQ
authors.lastname: Yu
authors.forename: X Z
authors.initials: XZ
authors.lastname: Yao
authors.forename: Z R
authors.initials: ZR
authors.lastname: Lu