Analytical Sciences

Highly Sensitive Extractive Spectrophotometric Determination of Palladium(II) in Synthetic Mixtures and Hydrogenation Catalysts Using Benzildithiosemicarbazone

B. Krishna REDDY, K. Janardhan REDDY, J. Rajesh KUMAR, A. Kiran KUMAR, and A. Varada REDDY

Analytical Division, Department of Chemistry, Sri Venkateswara University, Tirupati-517 502, A.P., India

A simple and highly sensitive method was developed for the extractive-spectrophotometric determination of palladium with benzilidithiosemicarbazone. The metal ion formed a reddish brown complex with benzildithiosemicarbazone in a potassium chloride-hydrochloric acid buffer of pH 2.5, which was easily extractable into methyl isobutyl ketone. The 1:1 complex showed the maximum absorbance at 395 nm with a Beer’s law range of 0.25 - 3.5 ppm. The molar absorptivity and Sandell’s sensitivity were found to be 3.018 × 10⁴ dm³ mol^-1 cm^-1 and 0.0035 µg cm^-2, respectively. The correlation coefficient of the Pd(II)-BDTSC complex was 0.998, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.46%. The instability constant of the complex calculated from Edmond and Birnbaum’s method was 2.41 × 10^-5, that of Asmus’ method is 2.53 × 10^-5 at room temperature. The interfering effects of various cations and anions were studied. The proposed method was successfully applied to the determination of palladium(II) in synthetic mixtures and hydrogenation catalysts. The validity of the method was tested by comparing the results with those obtained using an atomic absorption spectrophotometer.

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