Neue Bestimmungsmethode für organisch gebundenes Jod,Brom und Chlor

The catalytic dehalogenation with sodium tetrahydroborate enables rapid and simple halogen determinations especially in solutions, for example of X-ray contrasters. Organic bound iodine (in water, resp. dimethylformamide) is splitted off by NaBH₄ in the presence of palladium under stirring within 15 min at room temperature. More stable bromine and chlorine compounds need 10 min boiling of the reaction mixture with palladium on charcoal. After decomposition of the excessive sodium tetrahydroborate with acetone and addition of sulphuric acid, the halide ions are titrated potentiometrically in the known manner with silver nitrate solution using a silver/silver chloride electrode. Poisoning of the catalyst and volatility of the sample are possible disturbances.