Derivatisering

Derivatisering, or derivatization, is a chemical modification in analytical chemistry where a compound is transformed into a derivative by introducing a new functional group. The goal is to alter properties such as volatility, stability, solubility, or detectability to improve analysis or compatibility with a chosen analytical technique. Derivatization is commonly used in sample preparation for chromatographic separation and detection, and can also enhance ionization efficiency in mass spectrometry.

Purposes include enabling gas chromatography by increasing volatility and thermal stability, improving detection sensitivity by adding chromophores or fluorophores, enhancing ionization in MS, masking reactive groups, or facilitating stereochemical or chromatographic differentiation. Derivatization can also stabilize labile compounds or simplify data interpretation.

Common methods and reagents include silylation (for example BSTFA or MSTFA) to form trimethylsilyl derivatives; acylation or esterification to modify functional groups; formation of hydrazones or oximes for carbonyl compounds (e.g., DNPH); and tagging with chromogenic or fluorogenic reagents such as dansyl chloride or o-phthalaldehyde derivatives for amino acids. In practice, derivatization is tailored to the analyte, the intended detector, and the matrix.

Applications span environmental, clinical, pharmaceutical, and forensic analyses, as well as metabolomics and proteomics. It is widely employed in GC–MS, LC–MS, and HPLC with UV or fluorescence detection. Considerations include achieving complete and stable derivatization, avoiding side reactions, compatibility with solvents and instruments, and ensuring proper calibration and method validation.