the absorbance of the blue quaternary ammonium ion-association complexes does not vary with temperature , however , and the quaternary ammonium compounds can be determined without interference by amines because of the disappearance of the red species at 60 degrees . methylephedrine , diphenhydramine , ephedrine ( amines ) , benzethonium and/or berberine ( quaternary ammonium compounds ) in two- and three-component mixtures can be determined by using the thermochromism effect .
C0002508
amines
C0578399
quaternary