- Posts: 18
- Joined: Fri May 31, 2013 5:01 am
I have questions regarding measurement method difference between GC/FID and GC/MS.
For the quantitation of ambient VOCs, we use GC/FID type. GC/MS also has qequipped with thermal desorption type like GC/FID system.
Our GC/FID sytem has preconcentration type(Tenax TA, 20mg) + GC/FID sytem to monitor VOCs in ambient air. Calibration ranges are 5~20ppbv(5, 20, 50ppbv)using diluter with 10ppm standard gas cylinder.
When I compare the individual concentration(e.q. Toluene, m,p-Xylene) between GC/FID and GC/MS, toluene concentrations are very similar each other.
But m,p-xylene concentrations are too much different. Usually, GC/MS concentration has 1.6times(n=5) higher than GC/FID type.
Would anybody tell me this difference or recommend something?