In Gas Chromatography (GC), the carrier gas is the mobile phase that moves the sample through the column. It must be pure, inert, and dry so it doesn’t react with the sample or the stationary phase.
Here are the common carrier gases used:
1. Helium (He)
- Most commonly used.
- Inert, non-flammable, and gives good efficiency and sensitivity.
- Works well with many detectors, especially FID and TCD.
2. Nitrogen (N₂)
- Inexpensive and safe to use.
- Gives sharp peaks but slower analysis compared to helium or hydrogen.
- Commonly used when cost is a concern.
3. Hydrogen (H₂)
- Gives fast analysis and high efficiency.
- Works well with FID and TCD detectors.
- Flammable, so it must be handled carefully.
4. Argon (Ar)
- Used less often.
- Sometimes used with Electron Capture Detector (ECD) because it improves sensitivity.
In short:
The main carrier gases in GC are helium, nitrogen, hydrogen, and argon — chosen based on speed, safety, cost, and detector type.