Separation of Aromatic Amines by Thin-Layer and High-Performance Liquid Chromatography

Abstract

This paper reports two complementary methods for the analysis of primary aromatic amines in a mixture: a thin-layer chromatographic method for rapid screening with a low-nanogram detection level, and a high-performance liquid chromatographic (HPLC) method, with a picogram detection capability. Thin-layer chromatograms are developed by diazotization of the amines with nitrous oxide vapor, followed by coupling with N-(1-napthyl) ethylenendiamine dihydrochloride to produce sharp spots with distinctly different colors. Separation by HPLC is accomplished on a cyanopropyl-bonded phase column with ultraviolet (254nm) detection using hexane-isopropanol as the mobile phase without pH suppression.