A. Praveen Kumar

Simple and Simultaneous Method for Determination of Palladium(II) and Ruthenium(III) using Second-Order-Derivative Spectrophotometry

Abstract A simple, sensitive, and selective second-order-derivative spectrophotometric method has been developed for the simultaneous determination of palladium(II) and ruthenium(III) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent (HMBATSC) reacts with Pd(II) and Ru(III) at pH 3.0, forming soluble yellowish green and dark brown species, respectively. Palladium and ruthenium present in the mixture were simultaneously determined without solving the simultaneous equations by measuring the second derivative amplitudes at 445 nm and 385 nm, respectively. Further, the Beers law was obeyed in the range 0.21–12.78 µg mL−1 and 0.25–13.42 µg mL−1 for Pd(II) and Ru(III), respectively. A large number of foreign ions did not interfere in the present method. The proposed method was successfully applied for the determination of palladium in hydrogenation catalysts and ruthenium in water samples.

Simultaneous Determination of Cobalt(II) and Nickel(II) by Fourth-Order Derivative Spectrophotometric Method Using 2-Hydroxy-3-Methoxy Benzaldehyde Thiosemicarbazone.

A simple and new simultaneous fourth derivative spectrophotometric method is proposed for the analysis of a two-component system containing cobalt(II) and nickel(II) without separation using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a chromophoric reagent. The reagent reacts with cobalt(II) and nickel(II) at pH 6.0, forming soluble brown and yellow colored species, respectively. Cobalt(II) and nickel(II) present in themixture are simultaneously determined without solving the simultaneous equations bymeasuring the fourth derivative amplitudes at 468.5 nm and 474.5 nm, respectively. The derivative amplitudes obey Beers law at 468.5 nm and 474.5 nm for Co(II) and Ni(II) in the range 0.059–3.299 μg mL−1 and 0.058–3.285 μg mL−1 respectively. A large number of foreign ions do not interfere in the present method. The present simultaneous method is used for the determination of micro amounts of cobalt in biological samples, nickel in plant samples, and in some alloy steels and soil sample.

Spectrophotometric Determination of Gold(III) Using 2-Hydroxy-3-Methoxy Benzaldehyde Thiosemicarbazone as a Chromophoric Reagent

A chromophoric reagent, 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC), was employed for the sensitive spectrophotometric determination of gold(III). The gold(III) ion forms a blue-coloured complex with HMBATSC in an aqueous dimethyl formamide at pH 6.0. The gold complex shows the absorption maximum at 385 nm, and Beers law was obeyed in the range 0.49–8.37 μg mL−1. The molar absorptivity and Sandells sensitivity were found to be 1.28×104 L mol−1 cm−1 and 0.015 μg cm−2, respectively. The complex shows 1 : 1 [Au(III) : HMBATSC] stoichiometry with a stability constant of 1.32×106. The interference effect of various diverse ions has been studied. In addition to zero-order, first- and second-order derivative spectrophotometric methods were also developed for the determination of gold(III) in microgram amounts which were more sensitive than the zero-order method. The developed method has been used for the determination of gold(III) in environmental water samples and certified reference materials. The results were in excellent agreement with the certified values.