STUDY OF INTERACTION OF HEXAIODOPLATINATE(IV) WITH THIAZINE RAW DYE TETRAMETHYLTHIONINE IN SULFURIC ACID MEDIUM

Abstract

  An interaction between platinum(IV) iodide acidocomplex and thiazine raw organic basic dye tetramethylthionine has been studied. Compound forming in the system is extracted by dichloroetane–carbon tetrachloride (1:1) binary mixture. Maximal light absorbance (extinction) for extracts of forming compound as well as for “blind” extracts is observed at 655 nm wavelength. 

  At the optimal acidity conditions (pH 1.0 by sulfuric acid) platinum(IV) is extracted almost quantitatively (R = 97.7%) to the organic solvent phase by means of single extraction during 2 minutes’ shaking. The formed ionic associate is stable during 50 hours’ period. The optimal concentration of potassium iodide is 0.4–0.6 mL·10^–2 mol/L; optimal quantity of tetramethylthionine is secured by the addition of 1.4–2.0 mL of 0.05% solution of the dye.

  Dichloretane–carbon tetrachloride extracts of colored compound submit to the photometry main law (Beer’s law) in the range of platinum(IV) content in aqueous phase 2.49-89.59 mcg/10 mL. The molar coefficient of extinction  ε₆₅₅ = 7.65 · 10⁴ L· mol^-1·cm^-1, C_min = 0.02 mcg Pt/mL (P = 0.95).

  The influence of a series of interfering and accompanying elements on the determination of the platinum(IV) has been studied. An extraction-absorptiometric method for determination of platinum by tetramethylthionine has been elaborated.