Abstract
A sample salt of about 0.4g is treated with 8ml of 6M hydrochloric acid at 120°C for 30 min in a 23ml polytetrafluoroethylene decomposition vessel which is set in a stainless steel housing (UNI-SEAL), to prepare the sample solution. If residue is found in the sample solution, it is subjected to centrifuge separation and decomposition with hydrofluoric and sulfuric acids for determining undissolved aluminum. The solution is adjusted to pH 4.5 with ammonium acetate solution followed by adding small amounts of ascorbic acid. Aluminum is fluorometrically determined after adding 8-hydroxyquinoline-5-sulfonic acid. Aluminum down to about 0.2ppm is determined. Some analytical examples are given together with discussion about the effect of sodium chloride concentration and coexisting ions, decomposition of sample, and the dissolved and undis solved aluminum.
