Spectroscopic analysis of alcohols and phenols:

 The IR spectra of alcohols and phenols provide characteristic broad O-H stretching absorptions in the region 3600-3200 cm^-1.  Than the N-H absorptions these absorptions are broader but are not as broad since the O-H absorption of a carboxylic acid.

The precise position of the absorption depends upon the extent of hydrogen bonding in the sample. The much more H-bonding that is present the broader the absorption and the lower the wave number. Absorption because of O-H bending may be visible in the region 1410-1260 cm^-1, but this is within the fingerprint region and can easily be confused with other absorptions. Absorptions because of C-O stretching also take place in the fingerprint region, but can occasionally be distinguished as they tend to be stronger than surrounding absorptions. They take place in the regions 1075-1000 cm^-1 for primary alcohols, 1125-1100 cm^-1 for secondary alcohols, 1210-1100 cm^-1 for tertiary alcohols, and 1260-1140 cm^-1 for phenols.

The OH proton is observable in the ¹H nmr spectra of alcohols and phenols, generally like a broad signal in the region 0.5-4.5 ppm for alcohols and 4.5-10 ppm for phenols. The signal is lost if the sample is shaken along with deuterated water. The existence of an alcohol can sometimes be pointed out indirectly by the chemical shifts of neighboring groups. For instance, a methylene unit next to OH appears at 3.6 ppm in the ¹H spectrum. Carbon atoms next to OH depict signals in the range 50-80 ppm in the ¹³C spectrum.

The mass spectra of alcohols frequently lack the molecular ion as dehydration can take place rapidly to give a fragmentation ion 18 mass units less than the parent ion. Fragmentation as well occurs by α-cleavage that is cleavage, next to the carbon, which is bonded to the OH.