Indirekte photometrische Bestimmung kleiner Jodmengen in Selen

After separation of selenium by precipitation with ferrous iron, the iodine is employed for catalyzing the Ce⁴⁺/As³⁺-redox reaction. This is stopped by ferrous iron and the ferric iron formed is determined by photometry as thiocyanate. This method enables the determination of about 100 ± 6 ng of iodine in 5–10 mg of selenium. The method was applied for determination of the distribution of iodine in Se-rectifier layers. The layers were dissolved by etching with a solution of alkali cyanide. The usual doping elements showed no disturbance.