INTERACTION OF CHLORRHODIAT(III) COMPLEX WITH THIAZINE RAW DYE DIMETHILTHIONINE IN HYDROCHLORIC ACID BY EXTRACTION-ABSORBCIOMETRIC METHOD

Abstract

An interaction between rhodium(III) chlorice acidocompiex and thiazine raw organic basic dye dimethylthionine was studied. Compound forming in the system is extracted by dichloroethane–carbon tetrachloride (2.5+2.5 mL) binary mixture. Maximal light absorbance (extinction) for extracts of forming compound as well as for blind extracts is observed at 620 nm wavelenght. At the optimal acidity conditions (pH 1.0 by hydrochloric acid) rhodium(III) is extracted almost quantitatively (R=94%) to the organic solvent phase by means of single extraction during 1 minute. The shaking optimal quantity of dimethylthionine is secured by the addition of 1.0–1.4 mL of 0.05% solution of the dye. Dichlorethane–carbon tetrachloride–aceton extracts of coloured compound submit to the photometry main law in the range of rhodium(III) content in aqueous phase 5.48–43.8 mkg/10 mL. The molar coefficient of extinction is  ε₆₂₀=1.3–10⁴ L· mol^-1·cm^-1. C_mn=0.03 mkg Rh/mL. The influence of a series of interfering and accompanying elements on the determination of the rhodium(III) has been studied. An extraction-absorptiometric method for determination of rhodium by dimethylthionine has been elaborated.