Spectrophotometric Determination of Cobalt,Nickel and Palladium after Extraction with Thioxanthate into Molten Naphthalene

Cobalt, nickel and palladium have been extracted with thioxanthate into molten naphthalene (85–90°C). Various parameters involved in the extraction have been studied and composition of the extracted complex established in each case. Cobalt. nickel and palladium thioxanthates are extracted in the pH range, Co: 5.0–9.5. Ni: 3.9–7.4 and Pd: 2.0–9.5 and can be determined spectrophotometrically at 390. 500 and 345 nm respectively. The molar absorptivities are calculated to be Co: 6.187×10³ ? mol^?1 cm^?1, Ni: 8.8×10³ ? mol^?1 cm^?1 and Pd: 1.16×10⁴ ? mol^?1 cm^?1 with sensitivities in terms of Sandell's defication are; 0.0095 μg Co/cm² at 390 nm, 0.0060 μg Ni/cm² at 500 nm and 0.0091 μg Pd/cm² at 345 nm respectively. These conditions have been utilized for the determination of these metals in alloys and also for the simultaneous determination of cobalt and nickel in an alloy.