Nitrate determination by reduction to ammonia and gas-phase ultraviolet absorption spectrometry

Abstract

Nitrate can be rapidly reduced to ammonia by the action of titanium(III) sulphate, even at room temperature. Subsequent displacement of the ammonia by a current of air enables the gas-phase molecular absorbance of the ammonia to be measured and thus provides a sensitive and selective method for the determination of nitrate. Ions which affect the reduction of nitrate by titanium(III) salts interfere with the method and must be removed if present in large amounts.