Spectroscopic analysis:

Primary and secondary amines are probable to show characteristic absorptions because of N-H stretching and N-H bending. The former takes place in the region 3500-3300 cm^-1, and in the case of primary amines 2 absorptions are visible. The absorptions apt to be sharper but weaker than O-H absorptions can take place in the same region. N-H bending takes place in the region 1650-1560 cm^-1 for primary amines and 1580-1490 cm^-1 for secondary amines even though the latter tend to be weak and unreliable. These absorptions take place in the same region as alkene and aromatic C=C stretching absorptions and care has to be taken in assigning them.

In nature, these absorptions are not exists for tertiary amines. For aromatic amines, absorption because of Ar-N stretching may be shown in the region 1360-1250 cm^-1. The ¹H nmr spectrum of a primary or secondary amine will display a broad signal for the N-H proton in the region 0.5-4.5 ppm that will disappear from the spectrum if the sample is shaken along with deuterated water. For aromatic amines this signal is usually in the range 3-6 ppm. The chemical shifts of neighboring groups can as well point out the existence of an amine group indirectly. For instance, an N-methyl group provides a singlet near 2.3 ppm in the ¹H spectrum and appears in the region 30-45 ppm in the ¹³C spectrum. If the molecular ion in the mass spectrum comprises an odd number, this points out that an odd number of nitrogen atoms are present in the molecule. This supports the existence of an amine but does not prove it, because there are other functional groups consisting of nitrogen. Amines go through α-cleavage when they fragment (that is cleavage next to the carbon bearing the amine group.