SPECTROPHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF TITANIUM(IV), ZIRCONIUM(IV) AND THORIUM(IV) WITH MOLYBDOPHOSPHORIC ACID SOLUTION

Trace amounts of titanium(IV), zirconium(IV) and thorium(IV) ions were determined spectrophotometrically with molybdophosphoric acid solution. The method is based on the formation of the ternary heteropoly complex by reaction of the metal ion with molybdophosphoric acid, and the elimination of unreacted molybdophosphoric acid by extraction with n-butyl acetate. Beer's law was obeyed over the range 1-7 p.p.m. of metal ion. These ternary heteropoly complexes have the composition of Me:P:Mo= 1:1:12. The formation constants increase in the order, molybdotitanophosphate, molybdothorophosphate, and molybdozirconophosphate. © 1969.