derivatization

Derivatization is a chemical transformation in which a target molecule is converted into a derivative with altered physical, chemical, or analytical properties. The process is widely used to improve detection, separation, stability, or reactivity, without changing the underlying identity of the compound for purposes of study. Derivatives are typically formed by modifying a functional group such as an amine, carbonyl, or hydroxyl group.

In analytical chemistry, derivatization is often performed to enhance sensitivity or selectivity. It can increase volatility for gas chromatography, improve chromatographic behavior on liquid chromatography columns, introduce chromophores or fluorophores for UV/visible or fluorescence detection, or improve ionization efficiency in mass spectrometry. Derivatization may be performed before analysis (pre-column) or during the separation (post-column).

Common derivatization reactions include silylation to make compounds volatile for GC analysis; esterification or acylation to modify polarity; formation of hydrazones or oximes for carbonyl-containing compounds; and tagging with labeled or highly detectable reagents such as dansyl chloride for amines or fluorescent dyes for detection. In mass spectrometry, derivatization can stabilize labile groups or shift ionization pathways to improve signal.

In biochemistry and proteomics, derivatization and labeling are used for quantitative analysis. Examples include isotopic labeling of amino groups for mass spectrometry-based quantitation and N-terminus tagging in peptide workflows. In metabolomics and environmental analysis, derivatization enables detection of otherwise poorly detectable compounds.

Limitations of derivatization include incomplete reactions, side products, altered interpretation due to structural changes, and added cost or time. Careful optimization and proper controls are required to ensure that the derivative faithfully reflects the original compound's presence and concentration.