Analytical Sciences

Synthesis of N-o-Methylphenyl-N′-(sodium p-aminobenzene-sulfonate) thiourea and Its Chromogenic Reaction with Palladium(II)

Lei ZHANG,* Donglan MA,** Jianping LI,** and Yulu WANG**

*Department of Chemistry, College of Life and Environment Science, Shanghai Normal University, Guilin Rd100, Shanghai, 200234, China
**Department of Chemistry, College of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453002, China

A new chromogenic reagent, N-o-methylphenyl-N′-(sodium p-aminobenzenesulfonate)thiourea (MSAT), has been synthesized and characterized by elemental analysis, ¹H-NMR, FT-IR and UV-Vis spectra. Based on the absorption spectrum of the colored complex of MSAT with palladium(II), a novel spectrophotometric method for the determination of palladium has been developed. In a pH 4.0 - 5.5 HAc-NaAc buffer solution, palladium(II) reacted with MSAT to form a stable yellow water-soluble complex with an apparent molar absorptivity of ε = 2.04 × 10⁵ L mol^-1 cm^-1 at the maximum absorption of 318.0 nm. Beer's law was obeyed in the concentration range of 1.2 - 11.8 µg per 25 mL for palladium(II) with a correlation coefficient of 0.9997. The probable interfering ions and their tolerable limits have also been investigated in detail. The proposed method is simple, rapid, and sensitive, and has been applied to the determination of palladium in anode mud and ore samples with satisfactory results.

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