Spectrophotometric determination of platinum(IV) through the O-methylphenyl thiourea and iodide ternary complex after liquid-liquid extraction

Shashikant R. Kuchekar, Yogesh S. Shelar, Sung-Hwan Han

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A spectrophotometric method for the determination of platinum(IV) was developed using o-methylphenyl thiourea (OMPT). Platinum(IV) was determined as its ternary complex 1:1:2 (platinum(IV):OMPT:iodide) that is a yellow colored complex after liquid-liquid extraction from aqueous potassium iodide media (0.1 mol L-1) using 4.5×10-3 mol L-1 OMPT in 10 mL chloroform and is measured at 362 nm. Beer's law was obeyed in the concentration range up to 15 μg mL-1, with molar absorptivity and Sandell's sensitivity values of 1.25×104 L mol-1 cm-1and 0.016 μg cm-2 respectively. Repeatability of the method in terms of R.S.D was 0.34% (n=10). The stiochiometry of the platinum(IV)-OMPT-iodide complex was determined by the slope ratio method and verifi ed by mole and Job's continuous variation methods. The complex was stable for more than 48 h. The infl uence of various factors such as potassium iodide and OMPT concentrations as well as the extraction solvent and the time of equilibration have been established. The interference potential of a number of diff erent ions was evaluated and the use of masking agents is proposed. The developed method was successfully employed for the determination of platinum(IV) from binary synthetic mixtures, multicomponent synthetic mixtures, Adam's catalyst and pharmaceutical samples. The reliability of the method was assured by inter-comparison of experimental values with those obtained using atomic absorption spectrometry. A liquid-liquid extraction scheme is proposed for the separation of platinum(IV), palladium(II) and nickel(II) together.

Original languageEnglish
Pages (from-to)421-428
Number of pages8
JournalBrazilian Journal of Analytical Chemistry
Issue number10
Publication statusPublished - 2012 Oct 1



  • Liquid-liquid extraction
  • O-mehtylphenyl thiourea
  • Platinum(IV)
  • Spectrophotometry
  • Ternary complex

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