Typically the presence of an amine functional group is deduced by a combination of techniques, including mass spectrometry as well as NMR and IR spectroscopies. H NMR signals for amines disappear upon treatment of the sample with DO.  In their infrared spectrum primary amines exhibit two N-H bands, whereas secondary amines exhibit only one.  In their IR spectra, primary and secondary amines exhibit distinctive N-H stretching bands near 3300 cm.   Somewhat less distinctive are the bands appearing below 1600 cm, which are weaker and overlap with C-C and C-H modes.  For the case of propyl amine, the H-N-H scissor mode appears near 1600 cm, the C-N stretch near 1000 cm, and the RN-H bend near 810 cm.