Hi everyone,

I'm a new work on ATD system and struggling on the Extended Trap Des. Equil problem for a wile. :cry:

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.

As the error message occurs, we would not have any 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 before trap heating: https://www.dropbox.com/s/mj5efmq3rboak ... 8.mov?dl=0

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:
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

PE Clarus 580+ SQ8 MS
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