On the Colorimetric Determination of Oximes in Biological Materials

The method for the determination of oximes depends upon the colour reaction of nitrous acid. A pink colour develops when nitrous acid reacts with sulfanilic acid and α-naphthyl-amine. At first some supplementary experiments were made concerning the sensitiveness of this reaction. It is necessary that for the estimation of oximes these should be hydrolysed and then the formed hydroxylamine be oxidized to nitrous acid. The best procedures for the hydrolysis of oximes are as follows: to the solution containing oximes iodine-acetic acid and sulfanilic acid are added and the mixture is kept at 90° for 45 seconds. In order to avoid the destruction of hydroxylamine the follwing procedures are the most suitable for the oxidation of this amine: sulfanilic acid and iodine-acetic acid are mixed in the exam-ining solution and the resulting mixture is maintained at room temperature for 10 minutes. The reagents used were prepared in established ways.