Determination of molar ratio of primary secondary and tertiary amines in polymers by applying derivatization and NMR spectroscopy

A trifluoroacetic acid derivatization combined with 1H NMR spectroscopy method for determining the molar ratio of primary, secondary, and tertiary amines in small molecules and polymers was discussed. Amines reacted with trifluoroacetic acid to form their salts RNH3+, R2NH2+, and R3NH+. The 1H NMR signals of these protonated amines (NH3+, NH2+, and NH+) were separated well in the spectra. Based on the integration of these protonated amine signals, the molar ratio of primary, secondary, and tertiary amines can be calculated.