2-Methyl-1, 4-Naphthoquinone Thiosemicarbazone as a Sensitive and Selective Chromogenic Reagent for Microdetermination of Palladium (II)

A simple, sensitive and selective procedure has been developed for the spectrophotometric determination of palladium. Palladium (II) reacts with 2-methyl-1,4-naphthoquinone thiosemicarbazone to form an orange brown complex in the pH range 8.2–9.5. The sensitivity, in terms of Sandell's definition, is 0.0025 μg Pd/cm² at 500 nm. The system adheres to Beer's law upto 2.66 ppm of palladium and optimum concentration range for the determination of the metal is 0.3–2.29 ppm with molar absorbtivity of 4.2×10⁴ ? mole^?1 cm^?1. The complex has 1:1 molar composition, as deduced by Job's method. The determination of palladium has been carried out in presence of foreign ions especially in presence of eighth group metals.