Generally, a specific functional group of the compound participates in the derivatization reaction and transforms the educt to a derivate of deviating reactivity, solubility, boiling point, melting point, aggregate state, or chemical composition.
Derivatization techniques are frequently employed in chemical analysis of mixtures and in surface analysis, e.g. in X-ray photoelectron spectroscopy where newly incorporated atoms label characteristic groups.
By consulting an appropriate reference table such as in Vogel's, the identity of the starting material may be deduced.
However, due to the wide range of chemical compounds now known, it is unrealistic for these tables to be exhaustive.
The resultant product may be less polar, thus more volatile, allowing analysis by gas chromatography.