Colorimetric determination of titanium with phenylfluorone

Studies on organic reagents for inorganic analysis. III

Abstract

2, 2, 7-Trihydroxy-9-phenylfluorone reacts sensitively with titanium, and the coloration of the product is proportional to the amount of titanium. The sensitivity estimated from the slope of an estimation curve was 20 times as high·as that by the hydrogen peroxide method, twice as high as that by the titanium(III)-alizarin S method, and about the same as that by the conc. sulfuric acidthymol method. Thus, this is one of the most sensitive reactions. The titanium-phenylfluorone complex is difficultly soluble in many solvents. However, in contrast to other metal phenylfluoronates, it has the advantage of dissolving completely and forming no precipitate in a solution of above 0.1 N acid, while it has the disadvantage that the coloration is influenced by the presence of certain ions co-existing in an acid solution. These ions, such as Fe (III), Ge (IV), Sb (III) Sn (IV), and Zr (IV), have exhibited considerable interference.