The presence of 10 ppm of tartrate, citrate, phosphate, beryllium, magnesium, barium, calcium, manganese, sodium, potassium and 2 ppm of iron, lead, oxovanadium, platinum, gold did not interfere to the determination of 2 ppm of nickel or palladium. But cadmium, bismuth, copper and zinc introduced a positive error in determination of nickel and palladium when absorbance was measured at 380 nm and 357 nm respectively. However the palladium(II) also shows an absorption band at 470 nm(-4950 L mole' cm-) at pH 9, which is not observed in cadmium,cobalt,cobalt, copper(II), nickel(II) and zinco(Fig. 3). Thus, their interfering effect could
be eliminated by measuring the palladium absorbance at 470 nm, but with some loss in sensitivity.