The Spectrophotometric Determination of Ethylene Diamine with Phthalaldehyde and 2-Mercaptoethanol

Abstract A simple spectrophotometric method has been developed for the determination of ethylenediamine in an aqueous or ethanolic solution. This method is based on the reaction of ethylenediamine with phthalaldehyde and 2-mercaptoethanol, and on the measurement of the absorbance of the yellow-developed solution at 430 nm. Beer’s law holds for 0.5–10 μg of ethylenediamine per 1 ml. Secondary and tertiary amines do not interfere with theestimation. Two of the primary amines, diethylenetriamine and triethylenetetramine, interfere with the estimation when present in quantities of more than 10 μg per ml of the sample solutions. 1,3-Propanediamine interferes seriously. The colored compound was found to be composed of ethylenediamine, phthalaldehyde, and 2-mercaptoethanol in a molar ratio of 1:2:1.