# Gas chromatography flame ionization detector (FID) - why hydrogen gas?

Why is $$\ce{H2}$$ used in an FID, apart from the fact its combustion does not contaminate the flame?

In other words, is the temperature of the flame important or critical? Is the stability of the temperature?

• What alternative would you suggest ? E.g.a methane-air flame in FID would be like e.g using methylchloride as the makeup gas in ECD. – Poutnik May 19 at 12:43
• @Poutnik One alternative would be electric arc ionization. Another extreme UV. What is special about H2? – Dirk Bruere May 19 at 13:21
• It would be even much worse than methane. The key is to keep as low baseline ionisation as possible. That does not happen with methane flame and definitely not with arc or UV ionisation. With the arc, there would be additionally very high noise, several orders higher than useful signal. – Poutnik May 19 at 13:26