Interference Removal in Ammonium Measurement of Fermentation Broth by Berthelot Color Reaction

Sodium sulfite seriously interfered ammonium measurement in fermentation broth by Berthelot color reaction method.Pretreatment of samples by adding proper amount of sodium hypochloride was found effective to remove the interference.The adding amount of sodium hypochloride,pretreatment time and sample pH were investigated.It was confirmed by ion chromatography analysis that the ammonium concentration of the fermentation broth sample containing sodium sulfite,including some microorganism cells,could be determined satisfactorily by the Berthelot color reaction method modified.