A sensitive extractive spectrophotometric method for the determination of palladium(II) with 1, 3-bis(hydroxymethyl) benzimidazole-2-thione in catalysts

A simple, rapid and highly sensitive extraction method has been developed for the spectrophotometric determination of palladium(II) with 1,3-bis(hydroxymethyl)benzimidazole-2-thione[BHMBT] in methyl isobutylketone. The optimum perchloric acid range for the complexation is 0.7-3.5M. The yellow complex has an absorption maximum at 370 nm. Beer's law is obeyed up to 6.0 ppm of palladium(II). The optimum concentration range evaluated by Ringbom's method was found to be 1.32-5.01 ppm. The method of continuous variations, molar ratio method, and slope-ratio method confirmed a palladium(II) to BHMBT ratio of 1:1 in the complex. The molar absorptivity and Sandell's sensitivity were 1.543×10 4 L mole - 1 cm - 1 and 0.0068 μg cm - 2 , respectively. The optimum conditions have been investigated by studying parameters like effect of medium, effect of acidity, reagent concentration, time period, solvent and effect of diverse ions. The method has been applied successfully to the determination of palladium(II) in synthetic mixtures, corresponding to alloys and hydrogenation catalysts.