[citation needed] The term "structural analogue" is common in organic chemistry.
For example, melting point (MP) analysis can assist in identification of many organic compounds.
A crystalline derivative may be prepared, such as a semicarbazone or 2,4-dinitrophenylhydrazone (derived from aldehydes or ketones), as a simple way of verifying the identity of the original compound, assuming that a table of derivative MP values is available.
[3] Prior to the advent of spectroscopic analysis, such methods were widely used.
This reaction reduces the boiling point of the molecule, allowing non-volatile compounds to be analyzed by gas chromatography.