Peter Apps wrote:
If the FID detects terpenoids it will detect all the other organics as well. Therefore the problem is not with the detector. Where the problem is nobody can tell you because you do not tell us anything about your methods. If you want help rather than a string of guesses we need to know; all the temperatures and gas flows, column type and dimensions, inlet liner type and when you last did inlet maintenance, what concentration are you samples and what are they dissolved in, what volume are you injecting, split or splitless, split ratio if split.
Peter
I apologize for gaving not the whole information needed.
Here is the method for the aroma molecules diluted in propylene glycol in a concentration range from 2000(when not even higher) to 1 ppm. This method is also used at the GCMS which separates the desired aroma molecules in a good way.
Used column: HP5-MS (30m, 250µm, 0.25µm)
T(Inject)= 270 °C 1µl splitless, 1ml/min Helium (constant flow)
new splitless inlet liner original part from agilent, new septum
T(start) = 80(3 min) to 150 with 8 °C/min to 300°C(3min) with 15°C/min
T(FID) = 250 °C
flow(H2) = 30 ml/min flow(air)= 300 ml/min flow(N2)= 30 ml/min
(but I tried different flows of H2 and air but the ratio was always 1:10, quoted by Baars B. in a GC troubleshooting book as the best ratio for the FID)
Thank you