[The refractory susceptibility in determination of sulfur in organic drugs using the Schoniger method]

Conventional methods of the determination of sulphur in organic drugs were studied (Schöniger method) and new methods developed. Emphasis was put on the disturbance effect of 5 elements, which often occur in the structure of organic drug compounds. It could be shown, that the disturbance effect of nitrogen and chlorine was overcome by the use of carbamide and ammonium carbonate in the absorption solution. The effect of fluorine was abolished by the use of boric acid and a special two-spiral technique of the analysis. Based on these studies concrete recommendations for the Schöniger method of sulphur determination in drugs of various composition of elements were given.