Analytical derivatization — Why is chemical derivatization of analytes commonly performed before chromatographic analysis (especially GC)?

Introduction / Context:Derivatization modifies analyte functional groups to improve chromatographic behavior and detection. It is a key strategy in gas chromatography and sometimes in LC when sensitivity or selectivity needs enhancement.

Given Data / Assumptions:

• Polar functional groups (e.g., −OH, −NH2, −COOH) cause strong adsorption and tailing.
• Many detectors respond better to certain chemical moieties.
• GC requires analytes to be sufficiently volatile and thermally stable.

Concept / Approach:Assess each benefit: silylation, acylation, or alkylation reduces polarity; electron-capturing tags enhance ECD response; fluorescent or UV tags boost LC detector sensitivity; volatility and stability often improve, enabling cleaner peaks and better quantitation.

Step-by-Step Solution:

Verification / Alternative check:Compare chromatograms pre- and post-derivatization: reduced tailing, improved peak symmetry, and higher signal-to-noise validate the approach.

Why Other Options Are Wrong:

Common Pitfalls:Incomplete derivatization yields multiple peaks; always validate reaction completeness and stability.

Final Answer:All of the above.