Chromatography & Separation

GC

Gas Chromatography

GC separates the volatile compounds in a sample inside a heated column and measures each one as it elutes. It is a standard method for residual solvents, purity of volatile materials and fatty acid profiles.

1 test optionVolatile & semi-volatile compoundsppm-level detection with FIDTypical turnaround 4–6 working days
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GC measurement principleIllustrative
Carrier gasInjectorColumn ovenCapillary columnDetectorChromatogram
Vapours, sorted by the columnIllustrative
01 / Overview

What is GC?

Gas Chromatography vaporises a small liquid or gas sample and sweeps it through a long, thin capillary column with an inert carrier gas. Compounds travel at different speeds depending on boiling point and affinity for the column coating, and a detector records each one as a peak.

GC gives sharp, reproducible separation of volatile compounds and quantifies them precisely against standards. It identifies compounds by retention time only, so unknowns need GC-MS, and non-volatile or heat-sensitive compounds suit HPLC better.

02 / How it works

How it works

  1. 01

    Sample is injected

    About a microlitre of liquid, or headspace vapour, is injected into a heated inlet.

  2. 02

    Carrier gas sweeps it on

    The sample vaporises and an inert carrier gas carries it into the capillary column.

  3. 03

    Column separates compounds

    As the oven heats up, compounds leave the column in order of volatility and affinity.

  4. 04

    Detector records peaks

    Each compound gives a peak; its area is compared with standards to quantify it.

03 / What it measures

What it measures

Residual solvents

Quantify process solvents left in a product, usually by headspace GC.

Useful forAPIs, excipients, pharmaceutical intermediates

Purity (area %)

Estimate the purity of a volatile material from its peak areas.

Useful forSolvents, reagents, synthesised liquids

Fatty acid profile (FAME)

Fatty acid composition after conversion to methyl esters.

Useful forEdible oils, fats, biodiesel

Volatile components

Quantify known volatile compounds against reference standards.

Useful forEssential oils, flavours, fragrances

Gas composition

Permanent gases and light hydrocarbons, where the lab setup allows.

Useful forBiogas, process gases
04 / Test options

Choose the GC options you need

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GC test options
05 / Sample requirements

Sample requirements

Accepted forms
Liquids, oils, solutions in volatile solvent; solids for headspace
Quantity
2–5 mL liquid or 1–2 g solid per sample
Container
Sealed glass vials with PTFE-lined caps, little headspace
Standards
Send reference standards for uncommon compounds
  • Sealed glass vials, filled close to the top
  • List expected compounds, solvent and approximate concentration
  • Keep volatile samples cool during transit
  • No salts, suspended particles or non-volatile residues
  • No plastic bottles for solvent samples

Hazardous or air-sensitive samples: mention it in your request, and attach the MSDS if you have one.

06 / Results & turnaround

Results & turnaround

What you receive

  • Chromatogram for each sample
  • Retention times and peak areas
  • Area-% purity or concentration against standards
  • Method conditions (column, oven programme, detector)
  • Report PDF

Turnaround & pricing

Typically 4–6 working days after samples reach the lab.

Price confirmed in your quotation, depending on user type, options and number of samples.

Sample report · IllustrativeExample purity99.2 % (area)Illustrative — not measured sample data
07 / Limitations

When GC isn't the right fit

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