No Peaks - any help

[HPHealth]

Hi everyone,

Your help is crucial for my work progress. My concern is about solving an issue that I am facing - no peaks (attached images).

Here is the situation:
I have tried to run my gas permanent and light HC (O2, N2, CO2, C2H4, and N2O) last week and this week using Porapak Q Packed column 2m - ID 4mm. However, I am not getting the peaks.

Here is my conditions:
Using GC8340 CE (Carlo Erba) with NELSON PE 950/970a interface PC connected RS-232 - DIP switch 6 on. Interface connection with TCD: 1V not used 10V (considered as integrator not recorder?)
Isothermal, oven temp 80C, inject temp 50C.
TCD temp 120C and Filament is at 230C.
He as carrier gas at 40ml/min. increasing it to 50ml/min - same results
Using valve loop sample (5mL) for online analysis.
I have checked if there is any leak. No leak
Assuming the column and detector are okey.

If anyone from previous experience you has any pearls of wisdom or specific thoughts, they would be greatly appreciated.

Thanks in advance for your help and time.

[AICMM]

HPHealth,

Have you verified that the injection valve is actually turning by watching the bar sticking out of the end? Do you see a change in pressure when you inject? Do you have an inlet configured in that you can inject a uL of air into? Finally, have you tried cracking the column nut after the valve to introduce a touch of air? Divide and conquer, detector or injector.

Best regards,

AICMM

[HPHealth]

HPHealth,

Have you verified that the injection valve is actually turning by watching the bar sticking out of the end? Do you see a change in pressure when you inject? Do you have an inlet configured in that you can inject a uL of air into? Finally, have you tried cracking the column nut after the valve to introduce a touch of air? Divide and conquer, detector or injector.

Best regards,

AICMM

Thanks AICMM.

For the valve, I do it manually (fill/flush). While injecting, the pressure drops quickly and turns back to previous pressure.
For the inlet, I have the manual valve (fill/flush) and the inlet port inject. How to inject a uL of air?
I did not try cracking the column nut.
Divide and conquer, I am not familiar with the CE GC.

I have more information here:
The output on the software is about 6.5 mV (while running) When disconnecting TCD / AD connection, the baseline drops to about 0mV.

Thanks

[HPHealth]

I have obtained Peaks.
Thanks