Abstract
An improved method for the spectrophotometric determination of Sn (IV) with gallein was devised. Considerable reduction in time was achieved by the addition of oxalic acid and cetylpyridinium chloride. A spectrophotometric determination of oxalic acid was also established. A recommended procedure is as follows : To the solution of Sn (IV) are added 1.5 ml of 1.0×10-2M cetylpyridinium chloride solution, 0.3 ml of 1.0×10-3M C2O42- solution, and 1.0 ml of 1.0×10-3M methanolic gellein solution. To another solution of C2O42- are added 1.5 ml of 1.0×10-2M cetylpyridinium chloride solution, 0.5 ml of 5.0×10-4M Sn (IV) solution, and 0.2 ml of 1.0×10-3M methanolic gallein solution. A mixture of these two solutions is diluted to 10 ml with water and 3% sulfuric acid. The absorbance is measured at 530 nm for Sn (IX) and C2O42- after standing for 15 minutes at 25°.
