Resonance Rayleigh-Scattering Spectrometric Determination of Trace Amount of Iridium(Ⅳ) in Metallurgical Samples

In a dil.H2SO4 medium,an ion-associated complex was formed among Ir(Ⅳ),tungstate and Rhodamine B in the presence of polyvinyl alcohol.The maximum value of intensity of resonance scattering of complex was obtained at the wavelength of 612 nm.A new resonance Rayleigh-scattering spectrometric method for the determination of Ir(Ⅳ) was proposed on these basis.Under the optimum conditions,linear relationship was kept between the values of intensity of resonance scattering (ΔI) and mass concentration of Ir (Ⅳ) in the range of 0.5-7.5 μg·L-1 with the detection limit (3σ) of 0.25 μg·L-1.In its application to the analysis of 2 metallurgical samples,values of RSD′s (n=5) obtained were less than 1.3%.Results of recovery test found by standard addition method were in the range of 98.0%-103.0%.