EXTRACTION-SPECTROPHOTOMETRIC DETERMINATION OF LOW AMOUNTS OF ANTIMONY IN METALS AND ALLOYS

Modified extraction-spectrophotometric procedures have been used for determination of low amounts of antimony in various metallic materials. Use was made of the highly sensitive colour reaction of rhodamine B with the complex anion [SbCl6]- in the medium of HCl, wherefrom the coloured product was extractible into organic phase and the maximum of its absorbance was at lambda = 560 nm. Of the developed procedures the first one is based on direct extraction of the coloured product into toluene. In the second procedure first the [SbCl6]- anion is extracted with n-amyl acetate from the medium of HCl in the presence of NH4Cl. To the separated organic phase containing antimony, HCl, aqueous solution of rhodamine B, and toluene were added stepwise. By the procedures mentioned above it was possible to determine 3 x 10(-5) to 1 mass % Sb in various metallic materials.