A possibility of determination of rhodium(III) by Pyronin B oxine row basic dye in the hydrochloric medium has been studied. Ionic associate formed may be extracted by dichloroethanecarbon tetrachloride-acetone tri-component mixture (correspondingly 6, 4, 3 ml) from pH 2.0 hydrochloric medium. The maximal light absorption is observed at 545 nm wavelength. The optimal concentration of dye may be provided by addition of 1.0 ml 0.05 % solution. Linear dependence of the ionic associate optical absorption of the rhodium(III) concentration is observed within 0.73 - 14.63 mcg Rh per 10 ml solution range.
   An average value of the extinction molar coefficient is = 6.3 · 10⁴mol^-1 · l · cm^-1.