Applicable to all products having a titanium dioxide content of equal to or more than 0.001 % (m/m). Describes the preparation of the diantipyrylmethane solution and the preparation of the titanum standard solution. The procedure of the preparation of a principal solution or the chemical analysis by an alkaline fusion is carried out according to ISO 804 replacing the nitric acid solution by the sulphuric one. After extraction of the fused mass with sulphuric acid solution formation of the titanium-diantipyrylmethane complex (approximately 4.6 N solution). Photometric measurement of the coloured complex at a wavelength of about 420 nm. Has also been approved by the IUPAC. Replaces and cancels ISO Recommendation R 900/1968 of which it constitutes a technical revision.