Spectrophotometric determination of nickel in multi component alloys of nickel with titanium, zirconium, niobium and tantalum

Nickel in multi component alloys of Ni with Ti, Zr, Nb and Ta was determined by spectrophotometry using EDTA without prior separation. Hydrofluoric acid and hydrogen peroxide could be used as masking agents for the determination of Ni in the presence of coexisting elements of less than 300 mg. Procedure : a sample containing Ni below 140 mg was digested with 10 ml of nitric acid (1+1) and 2 ml of hydrofluoric acid in a platinum dish, 20 ml of saturated boric acid solution was added. The solution was put into a beaker containing 1 ml of hydrogen peroxide water, and 10 ml of EDTA (10 w/v%, pH 6) was added to the solution. After adjusting the pH to 5.5 with ammonia water, the solution was diluted to 100 ml with water in a volumetric flask. The absorbance of the final solution was measured at 1000 nm against reagent blank.