Selective spectrophotometric determination of palladium(II) with phenanthraquinone monothiosemicarbazone

Abstract

Palladium(II) forms two coloured complexes, a green complex at low pH and a brown complex at higher pH, with phenanthraquinone monothiosemicarbazone (PTS). Both of the complexes are soluble in dimethyl-formamide. PTS has been used for the spectrophotometric determination of Pd(II). The green and brown complexes have maximum absorbances at 590 and 540 nm and sensitivities of 0.025 and 0.0083 µg cm^–2 of Pd, respectively, for log l₀/l= 0.001. The optimum concentration ranges for the determination of Pd(II) are 3.4–18.2 and 1.3–6.7 p.p.m. for the green and brown complexes, respectively. The determination has also been carried out in the presence of foreign ions.