SIMULTANEOUS DETERMINATION OF PALLADIUM AND NICKEL IN ELECTROPLATING SOLUTIONS BY DIFFERENTIAL-PULSE POLAROGRAPHY

Differential-pulse polarography can be successfully employed for the simultaneous determination of palladium and nickel in electroplating baths. Both palladium and nickel give peaks in ammoniacal ammonium chloride and ammoniacal ammonium tartrate media that are separated by about 250 mV. When the nickel-to-palladium ratio exceeds 100, ethylenediaminetetraacetic acid (EDTA) may be added to complex nickel and thus remove the interference due to an excess of nickel. In the presence of large amounts of palladium, dimethylglyoxime is used to enhance the peak current of nickel. The palladium peak in ammoniacal ammonium chloride buffer at pH 9.0 is not affected by the presence of either EDTA or dimethylglyoxime. Hence it is possible to determine palladium and nickel simultaneously and in the presence of an excess of each other.