Chromatography Forum

Hi

Does anyone know the approximate detection threshold for methane with a GC with FID detector?

I have been detecting 1000ppm of methane but that seems to be the limit to what I can achieve. I was hoping to lower this although I don't know if this is realistic as I don't have much experience. Im using a GC with FID detector and a CTR dual column.

Ive tried playing with the injection/detector /column temp and pressure and Im also playing with split vs split less injection but are there any tips on how to lower the detection threshold?

Many thanks

Matt

With a packed column and 1 ml injection volume in the splitless mode, you can easily get to 1 ppm RL for methane with GC/FID.

Using a BP 1 (methyl silicone) capillary column 30m X 0.32 mm. Head pressure 15 psi, Injection temp 225 C. Column Temp 80 C, Detector Temp 250 C, Hydrogen as a carrier, split/splitless with a 2cc sample loop, I can detect .1 ppm methane easily . If you need further specs feel free to ask. Using an HP 5890 Series II.