Bromimetric titrimetry involving the determination of bromide ions and their oxidation products

Abstract

This paper describes some improvements in bromimetric titrimetry which are based on the determination of bromide and its oxidation products formed in the reaction instead of residual bromine. These modifications are particularly applicable to compounds capable of undergoing substitution or oxidation reactions. Substances which only undergo addition reactions do not affect the determination. The determination of bromide is based on oxidation with chloramine T to bromine in the presence of acetanilide, which acts as a bromine scavenger; the residual chloramine T is then determined. The bromine oxidation products of certain organic and inorganic compounds formed on reaction with excess bromine can be determined iodimetrically after the destruction of unreacted bromine with acetanilide. The methods have been tested for the determination of (i) bromide in pharmaceuticals, (ii) a variety of organic compounds through bromide formation (e.g., hydrazine, thiourea, allylthiourea, cystine, homocystine, methionine, phenol and aniline), (iii) certain substances through their oxidation product with bromine (e.g., cyanide, thiocyanate, thallium, 4-aminophenol, hydroquinone, 4-anisidine and thiosemicarbazide) and (iv) mixtures of thiocyanate and cyanide (in polluted water), hydroquinone, thiocyanate and metol (in photographic developers) and phenacetin and paracetamol (in drugs).