What is derivatization in GC analysis?

Derivatization in gas chromatography (GC) is a process in which a chemical modifies a compound to make it more suitable for GC analysis.

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Why Derivatization is Needed

• GC works best with volatile, thermally stable, and non-polar compounds.
• Many compounds (like sugars, amino acids, or alcohols) are polar, non-volatile, or unstable at high temperatures.
• Derivatization changes the chemical structure to improve:
  1. Volatility – so the compound can vaporize easily.
  2. Thermal stability – so it does not decompose in the GC column.
  3. Detectability – sometimes it improves response in detectors like FID or ECD.

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Common Types of Derivatization

1. Silylation – replaces active hydrogens (–OH, –NH, –SH) with a silyl group (e.g., trimethylsilyl).
2. Acylation – replaces hydrogen with an acyl group (–CO–R).
3. Alkylation – replaces hydrogen with an alkyl group (–CH3, –C2H5).

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How It Works

• The sample is reacted with a derivatizing reagent before injection.
• The derivative is now volatile and stable enough to pass through the GC column.
• After separation, the derivative is detected and quantified.

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In simple words:

Derivatization is like “preparing a sample for a hot GC ride.”
It modifies compounds that are normally hard to vaporize, making them easier to separate and detect in GC.