Hi everyone,
I hope you are all well.
I currently work on ATD-GC-MS for running VDA278 standard, but I experience the error message "Extended Trap Des. Equilibrium" on my ATD panel. As the error message occurs, we would not have peaks in my chromatography (just like a blank test). After I checked it, the problem is on the column flow rate could be unstable before trap heating.
The vedio I take for column flow unstable: https://www.dropbox.com/s/mj5efmq3rboaki0/2023-4-17%2005%2028.mov?dl=0
Nowadays, I run n-alkanes analysis with Tenax TA sorbent tube (methanol be the solvent, liquid solution directly spiking 1¬2µL on Tenax TA tube). Trap is packed by Tenax TA as well. The most tricky portion is this error always occur around two weeks after PE engineer maintenance. (While engineer here, the machine is running well. However, after running some tubes, the error occurs unpredictably) The system no leak be detected, air-water looks really nice.
So I'm wondering if anyone have the same issues before and willing to share your experience for trap desorption equilibrium extended.
These parameters for which I'm running now:
350ATD
Temperature(C)
Tube: 280
Transfer Line: 280
Valve: 280
Trap Low: -30
Trap High: 280
Trap Rate (C/s): 99
Times (min)
Tube Desorb: 20
Trap Hold: 20
Trap Desorb (Desorb2): 1
Purge: 1
GC Cycle: 85
Pneumatics (mL/m)
Inlet Split: 44
Outlet Split: 19
Tube Desorb: 40
Column: 2
Col/Trap Desorb: 2
GC Column: HP-ULTRA 2 50m, 0.32mm(Diam), 0.52 µm(Film)
GC Temperature: 40C for 2min, 3C/min to 92C, 5C/min to 160C, 10C/min to 280C holding 10min
Could it be that your cold trap packing material is moving around and sometimes creating channels? Sometimes it is packed firmly and sometimes it is loose.
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